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Fair Value Measurements - Unobservable Data Used in Recurring Valuations of Level 3 (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Level 3 [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, Fair Value	$ (845)
Interest Rate Swaps [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, Fair Value	753	$ 566
Cross-Currency Interest Rate Swaps [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, Fair Value	(842)	(986)
Cross-Currency Interest Rate Swaps [Member] | Level 3 [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, Fair Value	$ (801)
Discounted cash flow	Discounted cash flow
Cross-Currency Interest Rate Swaps [Member] | Fair Value Measurements Recurring [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Constant prepayment rate	Constant prepayment rate
Cross-Currency Interest Rate Swaps [Member] | Constant Prepayment Rate [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative, Basis Spread on Variable Rate	2.80%
Other [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, Fair Value	$ (7)	$ (2)
Other [Member] | Level 3 [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, Fair Value	(7)
Consumer Price Index/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member] | Level 3 [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, Fair Value	$ 10
Discounted cash flow	Discounted cash flow
Consumer Price Index/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member] | Fair Value Measurements Recurring [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Bid/ask adjustment to discount rate	Bid/ask adjustment to discount rate
Consumer Price Index/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member] | Bid/Ask Adjustment to Discount Rate [Member] | Minimum [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative, Basis Spread on Variable Rate	0.02%
Consumer Price Index/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member] | Bid/Ask Adjustment to Discount Rate [Member] | Maximum [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative, Basis Spread on Variable Rate	0.05%
Consumer Price Index/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member] | Bid/Ask Adjustment to Discount Rate [Member] | Weighted Average [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative, Basis Spread on Variable Rate	0.05%
Prime/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member] | Level 3 [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, Fair Value	$ (47)
Discounted cash flow	Discounted cash flow
Prime/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member] | Fair Value Measurements Recurring [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Constant prepayment rate	Constant prepayment rate
Bid/ask adjustment to discount rate	Bid/ask adjustment to discount rate
Prime/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member] | Bid/Ask Adjustment to Discount Rate [Member] | Minimum [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative, Basis Spread on Variable Rate	0.03%
Prime/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member] | Bid/Ask Adjustment to Discount Rate [Member] | Maximum [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative, Basis Spread on Variable Rate	0.05%
Prime/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member] | Bid/Ask Adjustment to Discount Rate [Member] | Weighted Average [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative, Basis Spread on Variable Rate	0.05%
Prime/LIBOR Basis Swaps [Member] | Interest Rate Swaps [Member] | Constant Prepayment Rate [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative, Basis Spread on Variable Rate	4.90%

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Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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