Fair Value Measurements - Fair Value of Assets and Liabilities Measured on Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative related liabilities	$ 0		$ (22)
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Due to affiliates carried at fair value	0		0
Derivative related liabilities			0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Due to affiliates carried at fair value	(496)		(514)
Derivative related liabilities			(22)
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Due to affiliates carried at fair value	0		0
Derivative related liabilities			0
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	0		0
Available-for-sale securities			80
Total assets	0		80
Due to affiliates carried at fair value	0		0
Derivative related liabilities	0		0
Total liabilities	0		0
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities			80
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	0		0
Derivative related liabilities	0		0
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Currency swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	0		0
Derivative related liabilities	0		0
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Derivative netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	0		0
Derivative related liabilities	0		0
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	1,107		1,683
Available-for-sale securities			0
Total assets	1,107		1,683
Due to affiliates carried at fair value	(496)		(514)
Derivative related liabilities	(337)		(1,630)
Total liabilities	(8,858)		(11,869)
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities			0
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	310		524
Derivative related liabilities	(309)		(1,585)
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Currency swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	797		1,159
Derivative related liabilities	(28)		(45)
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Derivative netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	0		0
Derivative related liabilities	0		0
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	0		0
Available-for-sale securities			0
Total assets	0		0
Due to affiliates carried at fair value	0		0
Derivative related liabilities	0		0
Total liabilities	0		0
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities			0
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	0		0
Derivative related liabilities	0		0
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Currency swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	0		0
Derivative related liabilities	0		0
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Derivative netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	0		0
Derivative related liabilities	0		0
Recurring [Member] | Netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	(1,107)	[1]	(1,683)	[1]
Available-for-sale securities			0	[1]
Total assets	(1,107)	[1]	(1,683)	[1]
Due to affiliates carried at fair value	0	[1]	0	[1]
Derivative related liabilities	337	[1]	1,608	[1]
Total liabilities	337	[1]	1,608	[1]
Recurring [Member] | Netting [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities			0	[1]
Recurring [Member] | Netting [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	0	[1]	0	[1]
Derivative related liabilities	0	[1]	0	[1]
Recurring [Member] | Netting [Member] | Currency swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	0	[1]	0	[1]
Derivative related liabilities	0	[1]	0	[1]
Recurring [Member] | Netting [Member] | Derivative netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	(1,107)	[1]	(1,683)	[1]
Derivative related liabilities	337	[1]	1,608	[1]
Recurring [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	0		0
Available-for-sale securities			80
Total assets	0		80
Due to affiliates carried at fair value	(496)		(514)
Derivative related liabilities	0		(22)
Total liabilities	(8,521)		(10,261)
Recurring [Member] | Fair Value [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities			80
Recurring [Member] | Fair Value [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	310		524
Derivative related liabilities	(309)		(1,585)
Recurring [Member] | Fair Value [Member] | Currency swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	797		1,159
Derivative related liabilities	(28)		(45)
Recurring [Member] | Fair Value [Member] | Derivative netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial assets	(1,107)		(1,683)
Derivative related liabilities	337		1,608
Long-term Debt Carried at Fair Value [Member] | Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long term debt	0		0
Long-term Debt Carried at Fair Value [Member] | Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long term debt	8,025		9,725
Long-term Debt Carried at Fair Value [Member] | Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long term debt	0		0
Long-term Debt Carried at Fair Value [Member] | Recurring [Member] | Netting [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long term debt	0	[1]	0	[1]
Long-term Debt Carried at Fair Value [Member] | Recurring [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long term debt	$ 8,025		$ 9,725

[1] Represents counterparty and swap collateral netting which allow the offsetting of amounts relating to certain contracts when certain conditions are met.