Condensed Consolidated Statements of Financial Condition (Parenthetical) - USD ($)		Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Available-for-sale investment securities, fair value	[1]	$ 10,503,000,000	$ 10,323,000,000
Available-for-sale investment securities, amortized cost	[1]	$ 10,016,000,000	$ 10,173,000,000
Common stock, par value per share (in dollars per share)		$ 0.01	$ 0.01
Common stock, shares authorized		2,000,000,000	2,000,000,000
Common stock, shares issued		567,529,990	566,653,650
Preferred stock, par value per share (in dollars per share)		$ 0.01	$ 0.01
Preferred stock, shares authorized		200,000,000	200,000,000
Preferred stock, shares issued		5,700	5,700
Preferred stock, shares outstanding		5,700	5,700
Preferred stock, liquidation preference (in dollars)		$ 570,000,000	$ 570,000,000
Treasury stock, shares		261,227,835	256,496,492

[1] Available-for-sale investment securities are reported at fair value.