Long-term Debt and Capital Lease Obligations Annual Maturities of Long-term Debt and Capital Lease Obligations (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Unamortized discount	$ (14)
Carrying Value	6,828	6,806
Amounts representing interest	(52)
Long-term Debt Repayments of Principal and Capital Leases Future Minimum Payments in Next Twelve Months	244
Long-term Debt Repayments of Principal and Capital Leases Future Minimum Payments Due in Two Years	129
Long-term Debt Repayments of Principal and Capital Leases Future Minimum Payments Due in Three Years	64
Long-term Debt Repayments of Principal and Capital Leases Future Minimum Payments Due in Four Years	63
Long-term Debt Repayments of Principal and Capital Leases Future Minimum Payments Due in Five Years	593
Long-term Debt Repayments of Principal and Capital Leases Future Minimum Payments Due Thereafter	5,850
Total Long-term Debt Maturities and Capital Leases Future Minimum Payments	6,943
Total long-term debt and capital lease obligations	6,877	6,861
Long-term Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	236
Long-term Debt, Maturities, Repayments of Principal in Year Two	122
Long-term Debt, Maturities, Repayments of Principal in Year Three	57
Long-term Debt, Maturities, Repayments of Principal in Year Four	52
Long-term Debt, Maturities, Repayments of Principal in Year Five	586
Long-term Debt, Maturities, Repayments of Principal after Year Five	5,789
Principal Amount	6,842
Unamortized discount	(14)
Carrying Value	6,828
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Capital Leases, Future Minimum Payments Due, Next Twelve Months	8
Capital Leases, Future Minimum Payments Due in Two Years	7
Capital Leases, Future Minimum Payments Due in Three Years	7
Capital Leases, Future Minimum Payments Due in Four Years	11
Capital Leases, Future Minimum Payments Due in Five Years	7
Capital Leases, Future Minimum Payments Due Thereafter	61
Capital Leases, Future Minimum Payments Due	101
Amounts representing interest	(52)
Capital Lease Obligations	$ 49