Significant Accounting Policies Significant Accounting Policics (Accumulated Other Comprehensive Loss) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ (136)	$ (158)
Other comprehensive income (loss) before reclassifications	(26)	13
Amounts reclassified from accumulated other comprehensive income	7	9
Other comprehensive income	(19)	22	0
Ending balance	(155)	(136)	(158)
Net Unrealized Gain/(Loss) on Derivatives [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(4)	(4)
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income	0	0
Other comprehensive income	0	0
Ending balance	(4)	(4)
Net Unrealized Gain/(Loss) on Investments [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(6)	(8)
Other comprehensive income (loss) before reclassifications	1	2
Amounts reclassified from accumulated other comprehensive income	0	0
Other comprehensive income	1	2
Ending balance	(5)	(6)
Benefit Obligations [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(126)	(148)
Other comprehensive income (loss) before reclassifications	(25)	13
Amounts reclassified from accumulated other comprehensive income	7	9
Other comprehensive income	(18)	22
Ending balance	(144)	(126)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	0	2
Other comprehensive income (loss) before reclassifications	(2)	(2)
Amounts reclassified from accumulated other comprehensive income	0	0
Other comprehensive income	(2)	(2)
Ending balance	$ (2)	$ 0