Basis Of Presentation Derivative Instruments (Details) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2015 USD ($) Interest_Rate_Swaps	Jun. 30, 2014 USD ($)	Sep. 30, 2013 Interest_Rate_Swaps	Jun. 30, 2015 USD ($) Interest_Rate_Swaps	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Swap [Member]
Derivative [Line Items]
Notional value of derivative instrument	$ 1,025			$ 1,025
Swap One [Member]
Derivative [Line Items]
Notional value of derivative instrument	225			225
Swap Two [Member]
Derivative [Line Items]
Notional value of derivative instrument	200			200
Swap Three [Member]
Derivative [Line Items]
Notional value of derivative instrument	200			200
Swap Four [Member]
Derivative [Line Items]
Notional value of derivative instrument	200			200
Swap Five [Member]
Derivative [Line Items]
Notional value of derivative instrument	200			200
Foreign Exchange Contract [Member]
Derivative [Line Items]
Notional value of derivative instrument	22			22		$ 27
Foreign Exchange Contract [Member] | Maximum [Member]
Derivative [Line Items]
Fair value of derivative instrument	1			1		1
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Operating Expense [Member]
Derivative [Line Items]
(Gain) or Loss Recognized on Derivatives	$ 0	$ 0		$ (1)	$ 0
Interest Rate Swap [Member]
Derivative [Line Items]
Number of interest rate derivatives held | Interest_Rate_Swaps	5			5
Number of Interest Rate Swaps Entered Into | Interest_Rate_Swaps			3
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member] | Interest Expense [Member]
Derivative [Line Items]
(Gain) or Loss Recognized on Derivatives	$ (3)	$ 14		$ 11	$ 22
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member] | Other Non-Current Liabilities [Member]
Derivative [Line Items]
Interest rate derivative liabilities, at fair value	$ 47			$ 47		$ 40