RIYADH—Saudi Arabia unveiled plans to free the kingdom from its dependence on oil revenues, in part by selling a stake in its state-owned oil company and creating the world’s largest sovereign-wealth fund.

The move represents an ambitious attempt to lay out a new economic trajectory for the country in an era of cheap oil. It is the brainchild of Deputy Crown Prince Mohammed bin Salman, the 30-year-old son of King Salman, who was entrusted by his father to oversee what are likely to be jarring changes in the kingdom.

“By 2020, we’ll be able to live without oil,” Prince Mohammed told Saudi-owned news channel Al Arabiya in an interview aired Monday. A detailed package of reforms included in the plan is expected to be released in six weeks.

Analysts said it could take Saudi Arabia many years to implement such far-reaching changes and fundamentally transform the economy.

Prince Mohammed on Monday presented a broad overview of what has been billed as the country’s most extensive economic shake-up in decades. Speaking to reporters, he said the project—dubbed “Saudi Vision 2030”—includes plans to sell less than 5% of state-owned oil giant Saudi Arabian Oil Co., known as Saudi Aramco, and transfer ownership of the company to Saudi Arabia’s sovereign-wealth fund, the Public Investment Fund, so it can build a war chest for non-oil investments abroad. The country will also implement reforms aimed at boosting revenue from non-oil sources, such as tourism and mining.

The prince said the reform plan doesn’t depend on fluctuations in the price of oil, and it can be achieved even if crude prices fall to around $30 a barrel. Oil has recently traded for around $45 a barrel. He added that the economic transition would be more about making spending more efficient than reducing it.

Saudi Arabia isn’t the first country in the region to propose long-term economic reform. The United Arab Emirates, Qatar and Kuwait have presented similar plans, though implementation has been slow in some countries.

The shift away from oil could fundamentally revise Saudi Arabia’s social contract. For decades the ruling monarchy indulged its population with generous spending and asked for no taxes in return.

Last year, oil provided 73% of state revenues, which in 2015 totaled about 608 billion riyals ($162 billion).

The prince, who also heads Aramco’s Supreme Council, its top decision-making body, estimated the company’s value between $2 trillion and $3 trillion. That would make Aramco more valuable than Apple Inc., Microsoft Corp. , Warren Buffett’s Berkshire Hathaway Inc. and Alphabet Inc., parent of Google, combined.

Based on those figures, listing 5% of the company could raise $100 to $150 billion. The prince said the company is working with banks on the public offering.

“We think Aramco’s size is very huge, not just for the Saudi market but even for the international market,” the prince said. “So we will open windows, the most important of which is in the American market, to trade in Aramco.”

With Aramco, Saudi Arabia’s Public Investment Fund would dwarf what is currently the world’s largest sovereign-wealth fund, Norway’s pension fund, which has assets worth around $825 billion, according to the Sovereign Wealth Fund Institute. Prince Mohammed estimated that the Saudi fund will eventually be worth nearly $3 trillion.

The swing away from oil is likely to come with requirements for more transparency of Saudi Arabia’s economy and companies—one of the prince’s stated goals. The moves would draw unprecedented scrutiny to Saudi Arabia’s oil assets and its finances more broadly.

The plan further empowers the young prince, who rose to a position of almost unchallenged power with his father’s ascension last year. The Saudi cabinet, in a statement carried by the official Saudi Press Agency, said the government’s economic council—headed by Prince Mohammed—would oversee the implementation of the overhaul.

“The plan is intended to develop a new social contract between the Al Saud family and its subjects,” says Theodore Karasik, of the Washington-based Gulf States Analytics. “In order to make the plan successful there needs to be unity behind Mohammed bin Salman, both at the local level and at the center.”

Saudi Arabia is also challenged by demographics, with some two-thirds of the population under 30 years old, which is forcing the monarchy to prioritize job creation to deal with an unemployment rate over 11%.

“Progress with reforms and moves to diversify the economy would have been vital, even if the oil prices stayed high,” says Monica Malik, chief economist at Abu Dhabi Commercial Bank. “The demographic challenge—the need to create jobs for the youth population—requires non-oil sector development.”

Prince Mohammed said the government aims to diversify its revenues by opening up to more privatization in areas like health care and education, as well as expanding the country’s manufacturing base and investing in alternative energy sources. He also said the kingdom would introduce fees on luxury items, tobacco and sugary drinks.

He reiterated the government wouldn’t introduce more extensive taxes, a sensitive issue in the Gulf. “Our commitment is clear: We won’t impose on the citizen any tax on income, capital or basic goods,” the document detailing the plan said.

Saudi Arabia’s new plan will take time to come into force. “2015 was the year of the quick fix, 2016 is the year of the more organized quick fix, and 2017 will be the year the vision will begin,” said Prince Mohammed, in the Al Arabiya interview.

He indicated the kingdom’s desire to move beyond its ultraconservative image, saying that Saudi Arabia would “open its doors to tourism of all nationalities in line with its tradition and values.” Currently, Saudi Arabia doesn’t issue tourist visas except to Muslim pilgrims.

The prolonged period of cheap oil—which Saudi Arabia has partly shaped by its decision not to curb production—has put a strain on state finances, and Riyadh has already taken some steps to address it. It has cut spending, issued domestic bonds and tapped its foreign-exchange reserves, which dropped by around $116 billion, or 16%, to $616.4 billion over the course of 2015. This month Saudi Arabia also turned to international banks for the first time in 25 years, sealing a $10 billion loan.

At the end of last year, the government took the difficult step of raising the domestic price of fuel, water and electricity. In a country where the population is accustomed to cheap utilities and no taxes, these changes have encountered some resistance.

The sudden rise in water prices—and billing mistakes that resulted in exorbitant charges for some—prompted a widespread backlash. Over the weekend, King Salman fired his minister of water and energy, Abdullah al-Hussayen, and temporarily handed the portfolio to the minister of agriculture.

The economic changes come at a politically sensitive time for Riyadh. The kingdom is engaged in a costly war in neighboring Yemen, where it suspects rival Iran is funding and supplying weapons to the Houthi rebels, something Tehran has denied.

More broadly, the kingdom is stepping up efforts to contain the influence of Iran, which is hoping to boost its own oil revenues. Last year’s nuclear deal lifted sanctions against Tehran in return for curbs on its nuclear program, paving the way for Iran’s re-entry into the world economy.

Saudi Arabia, wary that the deal could empower Iran to step-up its regional interference, has turned down requests from other oil producers to freeze production to prop up prices because a freeze would have excluded Iran.