Fair Value (Recurring Fair Value Measurements) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Assets
Securities available for sale, fair value	$ 44,519	$ 48,607
Trading securities	2,228	3,073
Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	44,157	48,174
Securities available for sale, fair value	44,519	48,607
Total financial derivatives	4,804	4,793
Trading securities	2,228	3,073
Trading loans	14	6
Total equity investments	1,793	1,664
Total customer resale agreements	194	207
Loans	884	1,025
Other assets	748	733
Total Assets	58,446	63,096
Liabilities
Derivative liabilities	3,834	3,934
Total trading securities sold short	875	1,342
Other borrowed funds	170	184
Total liabilities	4,879	5,460
Fair Value Additional Information [Abstract]
Fair value net derivative assets	2,043	1,695
Fair value net derivative liabilities	987	904
Net unrealized gains (losses)	32	11
Percentage of Trading securities - debt comprised of US Treasury and government agencies securities	59.00%	69.00%
Percentage of Trading securities - debt comprised of residential mortgage-backed securities	24.00%	17.00%
US Treasury and Government Agencies Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	5,367	4,118
Residential mortgage-backed Securities [Member] | Mortgage-backed Securities Agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	20,081	22,831
Residential mortgage-backed Securities [Member] | Mortgage-backed Securities Non-agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	5,341	5,605
Commercial mortgage-backed securities [Member] | Mortgage-backed Securities Agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	604	646
Commercial mortgage-backed securities [Member] | Mortgage-backed Securities Non-agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	3,558	4,042
Asset backed [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	5,438	5,772
State and Municipal [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	1,925	2,617
Other Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	1,843	2,543
Corporate Stocks And Other [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Securities available for sale, fair value	362	433
Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total financial derivatives	4,667	4,599
Liabilities
Derivative liabilities	3,173	3,326
BlackRock LTIP [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities
Derivative liabilities	335	332
Other Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total financial derivatives	137	194
Liabilities
Derivative liabilities	326	276
Residential Mortgage [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Loans held for sale	1,259	1,315
Mortgage servicing rights	967	1,087
Commercial Mortgage [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Loans held for sale	521	586
Mortgage servicing rights	515
Direct Equity Investments [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total equity investments	1,219	1,069
Fair Value Additional Information [Abstract]
Unfunded contractual commitments	29	36
Indirect Equity Investments [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total equity investments	574	595
Fair Value Additional Information [Abstract]
Unfunded contractual commitments	124	128
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	335	332
Other Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Other assets	413	401
Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Trading securities	2,207	3,053
Liabilities
Total trading securities sold short	875	1,342
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Trading securities	21	20
Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	4,723	3,460
Securities available for sale, fair value	5,070	3,877
Total financial derivatives	28	25
Trading securities	1,338	2,179
Other assets	194	209
Total Assets	6,630	6,290
Liabilities
Derivative liabilities	16	6
Total trading securities sold short	858	1,341
Total liabilities	874	1,347
Level 1 [Member] | US Treasury and Government Agencies Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	4,723	3,460
Level 1 [Member] | Corporate Stocks And Other [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Securities available for sale, fair value	347	417
Level 1 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total financial derivatives	28	25
Liabilities
Derivative liabilities	16	6
Level 1 [Member] | Other Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Other assets	194	209
Level 1 [Member] | Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Trading securities	1,317	2,159
Liabilities
Total trading securities sold short	858	1,341
Level 1 [Member] | Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Trading securities	21	20
Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	33,332	38,344
Securities available for sale, fair value	33,347	38,360
Total financial derivatives	4,735	4,732
Trading securities	857	862
Trading loans	14	6
Total customer resale agreements	194	207
Loans	524	513
Other assets	211	184
Total Assets	41,137	46,171
Liabilities
Derivative liabilities	3,364	3,489
Total trading securities sold short	17	1
Total liabilities	3,381	3,490
Level 2 [Member] | US Treasury and Government Agencies Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	644	658
Level 2 [Member] | Residential mortgage-backed Securities [Member] | Mortgage-backed Securities Agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	20,081	22,831
Level 2 [Member] | Residential mortgage-backed Securities [Member] | Mortgage-backed Securities Non-agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	234	247
Level 2 [Member] | Commercial mortgage-backed securities [Member] | Mortgage-backed Securities Agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	604	646
Level 2 [Member] | Commercial mortgage-backed securities [Member] | Mortgage-backed Securities Non-agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	3,558	4,042
Level 2 [Member] | Asset backed [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	4,819	5,131
Level 2 [Member] | State and Municipal [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	1,580	2,284
Level 2 [Member] | Other Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	1,812	2,505
Level 2 [Member] | Corporate Stocks And Other [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Securities available for sale, fair value	15	16
Level 2 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total financial derivatives	4,600	4,540
Liabilities
Derivative liabilities	3,150	3,307
Level 2 [Member] | Other Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total financial derivatives	135	192
Liabilities
Derivative liabilities	214	182
Level 2 [Member] | Residential Mortgage [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Loans held for sale	1,255	1,307
Level 2 [Member] | Other Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Other assets	211	184
Level 2 [Member] | Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Trading securities	857	862
Liabilities
Total trading securities sold short	17	1
Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	6,102	6,370
Securities available for sale, fair value	6,102	6,370
Total financial derivatives	41	36
Trading securities	33	32
Total equity investments	1,793	1,664
Loans	360	512
Other assets	343	340
Total Assets	10,679	10,635
Liabilities
Derivative liabilities	454	439
Other borrowed funds	170	184
Total liabilities	624	623
Level 3 [Member] | Residential mortgage-backed Securities [Member] | Mortgage-backed Securities Non-agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	5,107	5,358
Level 3 [Member] | Asset backed [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	619	641
Level 3 [Member] | State and Municipal [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	345	333
Level 3 [Member] | Other Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total debt securities	31	38
Level 3 [Member] | Interest Rate Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total financial derivatives	39	34
Liabilities
Derivative liabilities	7	13
Level 3 [Member] | BlackRock LTIP [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities
Derivative liabilities	335	332
Level 3 [Member] | Other Contracts [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total financial derivatives	2	2
Liabilities
Derivative liabilities	112	94
Level 3 [Member] | Residential Mortgage [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Loans held for sale	4	8
Mortgage servicing rights	967	1,087
Level 3 [Member] | Commercial Mortgage [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Loans held for sale	521	586
Mortgage servicing rights	515
Level 3 [Member] | Direct Equity Investments [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total equity investments	1,219	1,069
Level 3 [Member] | Indirect Equity Investments [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total equity investments	574	595
Level 3 [Member] | BlackRock Series C Preferred Stock | Fair Value, Measurements, Recurring [Member]
Assets
Other assets	335	332
Level 3 [Member] | Other Assets [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Other assets	8	8
Level 3 [Member] | Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Trading securities	$ 33	$ 32