Fair Value Measurements Level 3 Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Derivative, Gain (Loss) on Derivative, Net	$ (12)	$ 22	$ (14)	$ (77)
Fair Value, Measurements, Recurring [Member]
Liabilities, Fair Value Disclosure, Recurring	(445)		(445)		$ (749)
Fair Value, Measurements, Recurring [Member] | Level 3
Liabilities, Fair Value Disclosure, Recurring	(6)		(6)		$ (16)
Other Income (Expenses) [Member] | Embedded Derivatives in Preferred Units [Member]
Derivative, Gain (Loss) on Derivative, Net	$ 6	$ (1)	$ 10	$ (11)