Fair Values Of Assets And Liabilities Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount Exluded From Money Market Funds	$ 1,300,000,000		$ 1,600,000,000
Fair Value, Measurements, Recurring [Member] | Not Designated as Hedging Instrument [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	2,344,000,000		1,473,000,000
Liabilities Fair Value Disclosure	69,000,000		53,000,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	2,318,000,000	[1]	1,452,000,000	[1]
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	15,000,000		11,000,000
Derivative Liability	38,000,000		17,000,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Cap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	11,000,000		7,000,000
Derivative Liability	11,000,000		7,000,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0		3,000,000
Derivative Liability	$ 20,000,000		$ 29,000,000

[1] Excludes cash in banks of $1.3 billion and $1.6 billion at September 30, 2014 and December 31, 2013.