Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Available-for-sale securities, amortized cost	$ 34,863	$ 33,650
Held-to-maturity securities, fair value	$ 884	$ 1,204
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)	507,682,838	504,521,535
Common stock, shares outstanding (in shares)	299,324,357	337,940,636
Treasury stock, shares (in shares)	208,358,481	166,580,899