Comprehensive Income Accumulated Other Comprehensive Loss by Component (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Beginning balance	$ (245)
Other Comprehensive Income (Loss) before Reclassifications	(1)
Amounts reclassified from accumulated other comprehensive income (loss)	6
Accumulated Other Comprehensive Income (Loss), Ending balance	(240)
Equity Method Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Beginning balance	(4)
Other Comprehensive Income (Loss) before Reclassifications	(1)
Amounts reclassified from accumulated other comprehensive income (loss)	0
Accumulated Other Comprehensive Income (Loss), Ending balance	(5)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Beginning balance	(241)	[1]
Other Comprehensive Income (Loss) before Reclassifications	0	[1]
Amounts reclassified from accumulated other comprehensive income (loss)	(6)	[1]
Accumulated Other Comprehensive Income (Loss), Ending balance	$ (235)	[1]

[1] Amounts are net of tax.