Investments - Schedule of Available-For-Sale Investments (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Debt securities
Amortized cost	$ 11,486	$ 10,404
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Fair values	11,486	10,404
U.S. Treasury bills
Debt securities
Amortized cost	997	0
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Fair values	997	0
Money market mutual funds
Debt securities
Amortized cost	10,354	10,266
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Fair values	10,354	10,266
Other short-term interest-bearing securities
Debt securities
Amortized cost	135	138
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Fair values	$ 135	$ 138