Segment Reporting (Tables) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Net interest income	$ 9,108	$ 8,391	$ 8,278
Noninterest income	7,221	6,771	6,947
Total revenue	16,329	15,162	15,225
Provision for credit losses (benefit)	441	433	255
Depreciation and amortization	921	843	809
Other noninterest expense	9,477	8,633	8,654
Income before income taxes and noncontrolling interests	5,490	5,253	5,507
Income taxes (benefit)	102	1,268	1,364
Net income	5,388	3,985	4,143
Average Assets	371,769	361,260	354,964
Retail Banking
Segment Reporting Information [Line Items]
Net interest income	4,625	4,509	4,306
Noninterest income	2,236	2,693	2,781
Total revenue	6,861	7,202	7,087
Provision for credit losses (benefit)	347	297	253
Depreciation and amortization	177	175	187
Other noninterest expense	5,274	5,116	5,257
Income before income taxes and noncontrolling interests	1,063	1,614	1,390
Income taxes (benefit)	533	591	506
Net income	530	1,023	884
Average Assets	88,663	85,871	86,977
Corporate & Institutional Banking
Segment Reporting Information [Line Items]
Net interest income	3,396	3,181	3,144
Noninterest income	2,271	2,035	1,947
Total revenue	5,667	5,216	5,091
Provision for credit losses (benefit)	160	177	78
Depreciation and amortization	184	153	149
Other noninterest expense	2,244	2,069	2,038
Income before income taxes and noncontrolling interests	3,079	2,817	2,826
Income taxes (benefit)	615	908	934
Net income	2,464	1,909	1,892
Average Assets	148,414	140,309	133,754
Asset Management Group
Segment Reporting Information [Line Items]
Net interest income	287	300	292
Noninterest income	881	851	869
Total revenue	1,168	1,151	1,161
Provision for credit losses (benefit)	1	(6)	9
Depreciation and amortization	50	45	44
Other noninterest expense	813	780	802
Income before income taxes and noncontrolling interests	304	332	306
Income taxes (benefit)	102	122	112
Net income	202	210	194
Average Assets	7,511	7,707	7,920
BlackRock
Segment Reporting Information [Line Items]
Noninterest income	1,078	685	717
Total revenue	1,078	685	717
Income before income taxes and noncontrolling interests	1,078	685	717
Income taxes (benefit)	(686)	153	169
Net income	1,764	532	548
Average Assets	7,677	7,118	6,983
Other
Segment Reporting Information [Line Items]
Net interest income	800	401	536
Noninterest income	755	507	633
Total revenue	1,555	908	1,169
Provision for credit losses (benefit)	(67)	(35)	(85)
Depreciation and amortization	510	470	429
Other noninterest expense	1,146	668	557
Income before income taxes and noncontrolling interests	(34)	(195)	268
Income taxes (benefit)	(462)	(506)	(357)
Net income	428	311	625
Average Assets	$ 119,504	$ 120,255	$ 119,330