Condensed Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Millions		Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Available-for-sale investment securities, fair value	[1]	$ 20,573	$ 10,323
Available-for-sale investment securities, amortized cost	[1]	$ 20,148	$ 10,173
Common Stock, Par or Stated Value Per Share		$ 0.01	$ 0.01
Common Stock, Shares Authorized		2,000,000,000	2,000,000,000
Common Stock, Shares, Issued		567,743,876	566,653,650
Preferred Stock, Par or Stated Value Per Share		$ 0.01	$ 0.01
Preferred Stock, Shares Authorized		200,000,000	200,000,000
Preferred Stock, Shares Issued		10,700	10,700
Preferred Stock, Shares Outstanding		5,700	5,700
Treasury Stock, Shares		261,247,516	256,496,492

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