Securities - Realized Gain (Loss) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Mar. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Fair value of securities transferred from available-for-sale to held-to-maturity							$ 19,300,000,000
Net pre-tax unrealized gains (losses) in AOCI on securities on the date of transfer							(9,000,000)
Securities gains and losses
Realized gains	314,000,000		1,302,000,000		2,610,000,000
Realized losses	(233,000,000)		(614,000,000)		(457,000,000)
Net realized gains	81,000,000		688,000,000		2,153,000,000
Total credit losses recognized in income	(4,000,000)		(21,000,000)		(43,000,000)
Net securities gains	77,000,000	[1]	667,000,000	[1]	2,110,000,000	[1]
Other than temporary impairment losses investments portion previously recognized in earnings intends to sell net	3,000,000		12,000,000		24,000,000
Credit related
Securities gains and losses
Total credit losses recognized in income	(2,000,000)		(1,000,000)		(28,000,000)
Intent to sell
Securities gains and losses
Total credit losses recognized in income	$ (2,000,000)		$ (20,000,000)		$ (15,000,000)

[1] The following other-than-temporary impairment losses are included in securities gains for the periods presented.Year ended December 31, (in millions) 2014 2013 2012Debt securities the Firm does not intend to sell that have credit losses Total other-than-temporary impairment losses $(2) $(1) $(113)Losses recorded in/(reclassified from) accumulated other comprehensive income — — 85Total credit losses recognized in income (2) (1) (28)Securities the Firm intends to sell (2) (20) (15)Total other-than-temporary impairment losses recognized in income $(4) $(21) $(43)