Regulation and Capital Adequacy - Capital Rollforward (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Regulation And Capital Adequacy [Abstract]
Common Equity Tier 1, beginning balance	$ 63,248
Change in CET1 related to the transition to the Revised Capital Framework	3,656
Increase in common shareholders' equity	632	1,751
Change in deduction for goodwill and identifiable intangible assets, net of deferred tax liabilities	(22)
Change in deductions for investments in nonconsolidated financial institutions	(26)
Change in other adjustments	(73)
Common Equity Tier 1, ending balance	67,415	63,248
Tier 1 Capital, Beginning balance	72,471	66,977
Change in CET1 related to the transition to the Revised Capital Framework	3,656
Increase in perpetual non-cumulative preferred stock		1,000
Change in Tier 1 Capital related to the transition to the Revised Capital Framework	(219)
Other net increase in Common Equity Tier 1	511
Redesignation of junior subordinated debt issued to trusts	(688)	(687)
Change in goodwill and identifiable intangible assets		723
Change in equity investments in certain entities		1,491
Change in other adjustments	(323)	1,216
Tier 1 Capital, Ending balance	75,408	72,471
Tier 2 Capital, beginning balance	13,632	13,429
Change in Tier 2 Capital related to the transition to the Revised Capital Framework	(2)
Decrease in qualifying subordinated debt	(452)	(569)
Redesignation of junior subordinated debt issued to trusts	688	687
Change in other adjustments	27	85
Tier 2 Capital, Ending balance	13,893	13,632
Total Capital	$ 89,301	$ 86,103