Debt Debt Obligation Maturities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Debt Maturities [Abstract]
Debt maturities - 2014	$ 645
Debt maturities - 2015	363
Debt maturities - 2016	383
Debt maturities - 2017	715
Debt maturities - 2018	720
Debt maturities - Thereafter	14,180
Total Debt	17,006	[1]	14,533	[1]
Total Debt excluding capital leases	16,066	[2],[3]
Total Debt excluding capital leases, Fair Value	$ 16,507	[3]	$ 15,291	[3]
Weighted Average Interest Rate on Debt and Capital Lease Obligations [Abstract]
Weighted Average Interest Rate On Debt And Capital Lease Obligations - 2014	6.80%
Weighted Average Interest Rate On Debt And Capital Lease Obligations - 2015	5.20%
Weighted Average Interest Rate On Debt And Capital Lease Obligations - 2016	6.60%
Weighted Average Interest Rate On Debt And Capital Lease Obligations - 2017	5.70%
Weighted Average Interest Rate On Debt And Capital Lease Obligations - 2018	5.80%
Weighted Average Interest Rate On Debt And Capital Lease Obligations - Thereafter	5.10%
Total Debt, Weighted Average Interest Rate	5.30%

[1] Amounts represent debt outstanding and weighted average effective interest rates for 2013 and 2012, respectively. Maturities are as of December 31, 2013.

[2] Amount also excludes unamortized fair value adjustment under acquisition method accounting related to capital leases.

[3] Amount also excludes unamortized gains on interest rate swaps.