Segment Information - Schedule of Segment Reporting Information, by Segment (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Interest expense	$ 346	$ 369	$ 391
Operating Segments
Segment Reporting Information [Line Items]
Interest income	22	20	11
Interest expense	$ 30	$ 22	$ 22

Amount of the cost of borrowed funds accounted for as interest expense.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.9)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

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- Definition

Amount of operating interest income, including, but not limited to, amortization and accretion of premiums and discounts on securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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