Fair Value Measurements Derivative Instruments and hedging Activities Disclosure (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net Periodic Cash Settlements and Accrued Interest	$ 0	[1]	$ 43	[1]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 7		$ 8

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