Derivatives and Hedging Activities - Pre-Tax Net Gains (Losses) on Fair Value Hedges (Detail) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2015	Sep. 30, 2014
Derivatives, Fair Value [Line Items]
Net Gains (Losses) on Derivative	$ 157	$ 70
Net Gains (Losses) on Hedged Item	(66)	21
Other Income [Member] \| Interest Rate [Member]
Derivatives, Fair Value [Line Items]
Net Gains (Losses) on Derivative	66	(21)
Net Gains (Losses) on Hedged Item	(66)	21
Interest Expense [Member] \| Interest Rate [Member]
Derivatives, Fair Value [Line Items]
Net Gains (Losses) on Derivative	$ 91	$ 91

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 25

-Section 50

-Paragraph 1

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

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- Definition

Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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