Goodwill and Intangible Assets - Intangible Assets by Type (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Intangible Assets by Major Class [Line Items]
Gross carrying amount		$ 6,537	$ 6,558
Accumulated amortization		(2,756)	(2,716)
Net carrying amount		3,781	3,842	$ 4,047	$ 4,127
Finite-lived Intangible Assets
Intangible Assets by Major Class [Line Items]
Gross carrying amount	[1]	3,878	3,893
Accumulated amortization	[1]	(2,756)	(2,716)
Net carrying amount	[1]	$ 1,122	1,177
Finite-lived Intangible Assets | Weighted Average
Intangible Assets by Major Class [Line Items]
Remaining weighted- average amortization period	[1]	10 years
Finite-lived Intangible Assets | Customer relationships
Intangible Assets by Major Class [Line Items]
Gross carrying amount	[1]	$ 1,584	1,593
Accumulated amortization	[1]	(1,245)	(1,235)
Net carrying amount	[1]	$ 339	358
Finite-lived Intangible Assets | Customer relationships | Weighted Average
Intangible Assets by Major Class [Line Items]
Remaining weighted- average amortization period	[1]	11 years
Finite-lived Intangible Assets | Customer contracts—Investment Services
Intangible Assets by Major Class [Line Items]
Gross carrying amount	[1]	$ 2,256	2,260
Accumulated amortization	[1]	(1,481)	(1,450)
Net carrying amount	[1]	$ 775	810
Finite-lived Intangible Assets | Customer contracts—Investment Services | Weighted Average
Intangible Assets by Major Class [Line Items]
Remaining weighted- average amortization period	[1]	10 years
Finite-lived Intangible Assets | Other
Intangible Assets by Major Class [Line Items]
Gross carrying amount	[1]	$ 38	40
Accumulated amortization	[1]	(30)	(31)
Net carrying amount	[1]	$ 8	9
Finite-lived Intangible Assets | Other | Weighted Average
Intangible Assets by Major Class [Line Items]
Remaining weighted- average amortization period	[1]	3 years
Indefinite-lived Intangible Assets
Intangible Assets by Major Class [Line Items]
Gross carrying amount	[2]	$ 2,659	2,665
Net carrying amount	[2]	2,659	2,665
Indefinite-lived Intangible Assets | Customer relationships
Intangible Assets by Major Class [Line Items]
Gross carrying amount	[2]	1,303	1,307
Net carrying amount	[2]	1,303	1,307
Indefinite-lived Intangible Assets | Trade name
Intangible Assets by Major Class [Line Items]
Gross carrying amount	[2]	1,356	1,358
Net carrying amount	[2]	$ 1,356	$ 1,358

[1] Excludes fully amortized intangible assets.

[2] Intangible assets not subject to amortization have an indefinite life.