Fair Value Measurements Derivative Instruments and hedging Activities Disclosure (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net Periodic Cash Settlements and Accrued Interest	[1]	$ 0	$ 44	$ 0	$ 88
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		$ 0	$ 0	$ 7	$ 9

[1] The derivative settlements under the terms of the interest rate swap agreements were recognized as interest expense and were paid monthly or quarterly