Comprehensive Income Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning balance		$ 48	$ (2)
Other Comprehensive Income (Loss) before Reclassifications		(2)	(1)
Amounts reclassified from AOCI		0	0
Accumulated Other Comprehensive Income (Loss), Ending balance		46	(3)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning balance	[1]	50	0
Other Comprehensive Income (Loss) before Reclassifications	[1]	0	0
Amounts reclassified from AOCI	[1]	0	0
Accumulated Other Comprehensive Income (Loss), Ending balance	[1]	50	0
Equity Method Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning balance		(2)	(2)
Other Comprehensive Income (Loss) before Reclassifications		(2)	(1)
Amounts reclassified from AOCI		0	0
Accumulated Other Comprehensive Income (Loss), Ending balance		$ (4)	$ (3)

[1] Amounts are net of tax.