CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Securities available for sale, amortized cost	$ 100,336	$ 97,569
Securities available for sale, allowance for credit loss	1	1
Loans held for sale	$ 371	$ 596
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	6,650,000	4,975,000
Preferred stock, shares outstanding	6,650,000	4,975,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	683,559,818	679,932,837
Common stock, shares outstanding	446,113,769	458,972,202
Treasury stock, par value (in dollars per share)	$ 0.01	$ 0.01
Treasury stock, shares	237,446,049	220,960,635