Additional Financial Information - Accumulated Other Comprehensive (Loss) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Changes in accumulated other comprehensive income, gross
Accumulated other comprehensive income, beginning balance			$ (47)
Accumulated other comprehensive income, beginning balance	(82)	(31)	(47)
Changes in accumulated other comprehensive income, tax
Accumulated other comprehensive income, beginning balance			3
Accumulated other comprehensive income, beginning balance	(3)	(3)	3
Changes in accumulated other comprehensive income, net
Accumulated other comprehensive income, beginning balance			(44)
Accumulated other comprehensive income, ending balance	(85)	(34)	(44)
Accumulated Defined Benefit Plans Adjustment
Changes in accumulated other comprehensive income, gross
Adjustments for pension and other post-employment benefits, net of amortization	(51)	16
Changes in accumulated other comprehensive income, tax
Adjustments for pension and other post-employment benefits, net of amortization	0	(6)
Changes in accumulated other comprehensive income, net
Adjustments for pension and other post-employment benefits, net of amortization	$ (51)	$ 10

Accumulated Other Comprehensive Income (Loss), Tax

No definition available.

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- Definition

Amount before tax of increase (decrease) in accumulated in equity from transactions and other events and circumstances from non-owner sources. Excludes net income (loss), and accumulated changes in equity from transactions resulting from investments by owners (distributions to owners).

+ References

No definition available.

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

+ References

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Amount before tax, after reclassification adjustments of other comprehensive income (loss).

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount of tax expense (benefit) allocated to other comprehensive income (loss).

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