Condensed Consolidated Balance Sheet (unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Available-for-sale securities, amortized cost	$ 28,114	$ 28,416
Held-to-maturity securities, fair value	$ 4,633	$ 4,729
Common stock, par value per share (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,100,000,000	1,100,000,000
Common stock, shares issued (in shares)	514,161,006	511,861,447
Common stock, shares outstanding (in shares)	303,977,972	302,459,258
Treasury stock, common, shares (in shares)	210,183,034	209,402,189