Pledged Assets, Offsetting - Securities Financing Activities (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Financial Instruments Owned and Pledged as Collateral [Line Items]
Net amounts in consolidated balance sheet	$ 97,131	$ 80,933
Collateral received with the right to sell or repledge	131,200	108,500
Resale, Securities Borrowing and Similar Arrangements
Gross amounts recognized	113,611	92,446
Gross amounts offset in consolidated balance sheet	(16,480)	(11,513)
Net amounts in consolidated balance sheet	97,131	80,933
Collateral not recognized in consolidated balance sheet	(96,386)	(80,158)
Net amount	745	775
Repurchase and securities lending agreements
Gross amounts recognized	63,062	57,622
Gross amounts offset in consolidated balance sheet	(16,480)	(11,513)
Net amounts in consolidated balance sheet	46,582	46,109
Collateral pledged but not netted in consolidated balance sheet	(46,371)	(45,819)
Net amount	211	290
Collateral sold or repledged	47,200	36,100
Collateral pledged, fair value	64,600	59,200
Fed funds sold and securities purchased under resale agreements [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Net amounts in consolidated balance sheet	79,400	65,600
Resale, Securities Borrowing and Similar Arrangements
Net amounts in consolidated balance sheet	79,400	65,600
Loans [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Net amounts in consolidated balance sheet	17,700	15,300
Resale, Securities Borrowing and Similar Arrangements
Net amounts in consolidated balance sheet	$ 17,700	$ 15,300