Fair Value (Recurring Fair Value Measurements) (Details) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Assets
Securities available for sale, fair value	$ 43,620,000,000	$ 48,607,000,000
Trading securities	2,650,000,000	3,073,000,000
Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	43,223,000,000	48,174,000,000
Securities available for sale, fair value	43,620,000,000	48,607,000,000
Total financial derivatives	4,351,000,000	4,793,000,000
Trading securities	2,650,000,000	3,073,000,000
Trading loans	35,000,000	6,000,000
Total equity investments	1,788,000,000	1,664,000,000
Total customer resale agreements	191,000,000	207,000,000
Loans	1,017,000,000	1,150,000,000
Other assets	762,000,000	733,000,000
Total Assets	57,978,000,000	63,221,000,000
Liabilities
Derivative liabilities	3,547,000,000	3,934,000,000
Total trading securities sold short	1,366,000,000	1,342,000,000
Other borrowed funds	274,000,000	309,000,000
Total liabilities	5,187,000,000	5,585,000,000
Fair Value Additional Information [Abstract]
Fair value net derivative assets	1,834,000,000	1,695,000,000
Fair value net derivative liabilities	1,007,000,000	904,000,000
Net unrealized gains (losses)	35,000,000	11,000,000
Percentage of Trading securities - debt comprised of US Treasury and government agencies securities	51.00%	69.00%
Percentage of Trading securities - debt comprised of residential mortgage-backed securities	29.00%	17.00%
Mortgage-backed Securities Agency [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value Additional Information [Abstract]
Quantifying Misstatement In Current Year Financial Statements Amount		1,100,000,000
US Treasury and Government Agencies Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	5,343,000,000	4,118,000,000
Residential mortgage-backed Securities [Member] | Mortgage-backed Securities Agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	18,160,000,000	21,714,000,000
Residential mortgage-backed Securities [Member] | Mortgage-backed Securities Non-agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	5,138,000,000	5,605,000,000
Commercial mortgage-backed securities [Member] | Mortgage-backed Securities Agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	1,792,000,000	1,763,000,000
Commercial mortgage-backed securities [Member] | Mortgage-backed Securities Non-agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	3,788,000,000	4,042,000,000
Asset backed [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	5,123,000,000	5,772,000,000
State and Municipal [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	2,050,000,000	2,617,000,000
Other Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	1,829,000,000	2,543,000,000
Corporate Stocks And Other [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Securities available for sale, fair value	397,000,000	433,000,000
Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total financial derivatives	4,126,000,000	4,599,000,000
Liabilities
Derivative liabilities	2,893,000,000	3,326,000,000
BlackRock LTIP [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities
Derivative liabilities	345,000,000	332,000,000
Other Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total financial derivatives	225,000,000	194,000,000
Liabilities
Derivative liabilities	309,000,000	276,000,000
Residential Mortgage [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Loans held for sale	1,187,000,000	1,315,000,000
Mortgage servicing rights	978,000,000	1,087,000,000
Commercial Mortgage [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Loans held for sale	867,000,000	586,000,000
Mortgage servicing rights	532,000,000
Direct Equity Investments [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total equity investments	1,235,000,000	1,069,000,000
Fair Value Additional Information [Abstract]
Unfunded contractual commitments	28,000,000	36,000,000
Indirect Equity Investments [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total equity investments	553,000,000	595,000,000
Fair Value Additional Information [Abstract]
Unfunded contractual commitments	117,000,000	128,000,000
Number of years over which distributions from indirect equity funds are expected to be received	12 years
BlackRock Series C Preferred Stock | Fair Value, Measurements, Recurring [Member]
Assets
Other assets	345,000,000	332,000,000
Other Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Other assets	417,000,000	401,000,000
Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Trading securities	2,630,000,000	3,053,000,000
Liabilities
Total trading securities sold short	1,366,000,000	1,342,000,000
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Trading securities	20,000,000	20,000,000
Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	4,712,000,000	3,460,000,000
Securities available for sale, fair value	5,094,000,000	3,877,000,000
Total financial derivatives	2,000,000	25,000,000
Trading securities	1,353,000,000	2,179,000,000
Other assets	188,000,000	209,000,000
Total Assets	6,637,000,000	6,290,000,000
Liabilities
Derivative liabilities	2,000,000	6,000,000
Total trading securities sold short	1,352,000,000	1,341,000,000
Total liabilities	1,354,000,000	1,347,000,000
Level 1 [Member] | US Treasury and Government Agencies Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	4,712,000,000	3,460,000,000
Level 1 [Member] | Corporate Stocks And Other [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Securities available for sale, fair value	382,000,000	417,000,000
Level 1 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total financial derivatives	2,000,000	25,000,000
Liabilities
Derivative liabilities	2,000,000	6,000,000
Level 1 [Member] | Other Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Other assets	188,000,000	209,000,000
Level 1 [Member] | Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Trading securities	1,333,000,000	2,159,000,000
Liabilities
Total trading securities sold short	1,352,000,000	1,341,000,000
Level 1 [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Trading securities	20,000,000	20,000,000
Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	32,631,000,000	38,344,000,000
Securities available for sale, fair value	32,646,000,000	38,360,000,000
Total financial derivatives	4,320,000,000	4,732,000,000
Trading securities	1,263,000,000	862,000,000
Trading loans	35,000,000	6,000,000
Total customer resale agreements	191,000,000	207,000,000
Loans	634,000,000	623,000,000
Other assets	221,000,000	184,000,000
Total Assets	40,493,000,000	46,281,000,000
Liabilities
Derivative liabilities	3,046,000,000	3,489,000,000
Total trading securities sold short	14,000,000	1,000,000
Other borrowed funds	94,000,000	110,000,000
Total liabilities	3,154,000,000	3,600,000,000
Level 2 [Member] | US Treasury and Government Agencies Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	631,000,000	658,000,000
Level 2 [Member] | Residential mortgage-backed Securities [Member] | Mortgage-backed Securities Agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	18,160,000,000	21,714,000,000
Level 2 [Member] | Residential mortgage-backed Securities [Member] | Mortgage-backed Securities Non-agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	227,000,000	247,000,000
Level 2 [Member] | Commercial mortgage-backed securities [Member] | Mortgage-backed Securities Agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	1,792,000,000	1,763,000,000
Level 2 [Member] | Commercial mortgage-backed securities [Member] | Mortgage-backed Securities Non-agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	3,788,000,000	4,042,000,000
Level 2 [Member] | Asset backed [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	4,531,000,000	5,131,000,000
Level 2 [Member] | State and Municipal [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	1,704,000,000	2,284,000,000
Level 2 [Member] | Other Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	1,798,000,000	2,505,000,000
Level 2 [Member] | Corporate Stocks And Other [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Securities available for sale, fair value	15,000,000	16,000,000
Level 2 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total financial derivatives	4,097,000,000	4,540,000,000
Liabilities
Derivative liabilities	2,886,000,000	3,307,000,000
Level 2 [Member] | Other Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total financial derivatives	223,000,000	192,000,000
Liabilities
Derivative liabilities	160,000,000	182,000,000
Level 2 [Member] | Residential Mortgage [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Loans held for sale	1,183,000,000	1,307,000,000
Level 2 [Member] | Other Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Other assets	221,000,000	184,000,000
Level 2 [Member] | Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Trading securities	1,263,000,000	862,000,000
Liabilities
Total trading securities sold short	14,000,000	1,000,000
Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	5,880,000,000	6,370,000,000
Securities available for sale, fair value	5,880,000,000	6,370,000,000
Total financial derivatives	29,000,000	36,000,000
Trading securities	34,000,000	32,000,000
Total equity investments	1,788,000,000	1,664,000,000
Loans	383,000,000	527,000,000
Other assets	353,000,000	340,000,000
Total Assets	10,848,000,000	10,650,000,000
Liabilities
Derivative liabilities	499,000,000	439,000,000
Other borrowed funds	180,000,000	199,000,000
Total liabilities	679,000,000	638,000,000
Level 3 [Member] | Residential mortgage-backed Securities [Member] | Mortgage-backed Securities Non-agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	4,911,000,000	5,358,000,000
Level 3 [Member] | Asset backed [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	592,000,000	641,000,000
Level 3 [Member] | State and Municipal [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	346,000,000	333,000,000
Level 3 [Member] | Other Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	31,000,000	38,000,000
Level 3 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total financial derivatives	27,000,000	34,000,000
Liabilities
Derivative liabilities	5,000,000	13,000,000
Level 3 [Member] | BlackRock LTIP [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities
Derivative liabilities	345,000,000	332,000,000
Level 3 [Member] | Other Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total financial derivatives	2,000,000	2,000,000
Liabilities
Derivative liabilities	149,000,000	94,000,000
Level 3 [Member] | Residential Mortgage [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Loans held for sale	4,000,000	8,000,000
Mortgage servicing rights	978,000,000	1,087,000,000
Level 3 [Member] | Commercial Mortgage [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Loans held for sale	867,000,000	586,000,000
Mortgage servicing rights	532,000,000
Level 3 [Member] | Direct Equity Investments [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total equity investments	1,235,000,000	1,069,000,000
Level 3 [Member] | Indirect Equity Investments [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total equity investments	553,000,000	595,000,000
Level 3 [Member] | BlackRock Series C Preferred Stock | Fair Value, Measurements, Recurring [Member]
Assets
Other assets	345,000,000	332,000,000
Level 3 [Member] | Other Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Other assets	8,000,000	8,000,000
Level 3 [Member] | Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Trading securities	$ 34,000,000	$ 32,000,000