Fair Value Measurements And Disclosure (Fair Value Leveling) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	$ 335	$ 521
Cross-Currency Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	116	144
Liability Derivatives (at fair value)	(1,011)	(820)
Interest Rate Locks [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability Derivatives (at fair value)		(173)
Foreign Exchange Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	3	2
Liability Derivatives (at fair value)	(8)	(9)
Domestic Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale Securities (at fair value)	1,007	947
International Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale Securities (at fair value)	516	495
Fixed Income Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale Securities (at fair value)	444	562
Level 1 [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	0	0
Level 1 [Member] | Cross-Currency Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	0	0
Liability Derivatives (at fair value)	0	0
Level 1 [Member] | Interest Rate Locks [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability Derivatives (at fair value)		0
Level 1 [Member] | Foreign Exchange Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	0	0
Liability Derivatives (at fair value)	0	0
Level 1 [Member] | Domestic Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale Securities (at fair value)	1,007	947
Level 1 [Member] | International Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale Securities (at fair value)	516	495
Level 1 [Member] | Fixed Income Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale Securities (at fair value)	0	0
Level 2 [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	335	521
Level 2 [Member] | Cross-Currency Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	116	144
Liability Derivatives (at fair value)	(1,011)	(820)
Level 2 [Member] | Interest Rate Locks [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability Derivatives (at fair value)		(173)
Level 2 [Member] | Foreign Exchange Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	3	2
Liability Derivatives (at fair value)	(8)	(9)
Level 2 [Member] | Domestic Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale Securities (at fair value)	0	0
Level 2 [Member] | International Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale Securities (at fair value)	0	0
Level 2 [Member] | Fixed Income Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale Securities (at fair value)	444	562
Level 3 [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	0	0
Level 3 [Member] | Cross-Currency Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	0	0
Liability Derivatives (at fair value)	0	0
Level 3 [Member] | Interest Rate Locks [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability Derivatives (at fair value)		0
Level 3 [Member] | Foreign Exchange Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	0	0
Liability Derivatives (at fair value)	0	0
Level 3 [Member] | Domestic Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale Securities (at fair value)	0	0
Level 3 [Member] | International Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale Securities (at fair value)	0	0
Level 3 [Member] | Fixed Income Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-Sale Securities (at fair value)	$ 0	$ 0