Debt, Other Disclosures (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Principal Payments Due on Debt
2015	$ 601
2016	0
2017	950
2018	0
2019	750
Thereafter	4,074
Net unamortized discount and fair value adjustments	(21)	(24)
Total debt	6,354us-gaap_LongTermDebt	6,525us-gaap_LongTermDebt
Future Minimum Rental on Capital Lease Obligations
2015	8
2016	8
2017	6
2018	6
2019	6
Thereafter	18
Capital lease, net unamortized fair value adjustment	1
Less interest expense	(21)
Total capital lease obligations	$ 32us-gaap_CapitalLeaseObligations	$ 39us-gaap_CapitalLeaseObligations

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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- Details

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