Basis of Presentation and Significant Accounting Policies (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Assets
Deferred charges and other assets, net	$ 2,653	$ 2,626
Liabilities
Debt and capital lease obligations, less current portion	7,207	7,208
Deferred income taxes	$ 7,192	7,060
Adjustments for New Accounting Pronouncements [Member]
Assets
Current deferred income taxes		0
Deferred charges and other assets, net		2,626
Liabilities
Current deferred income taxes		0
Debt and capital lease obligations, less current portion		7,208
Deferred income taxes		7,060
Adjustments for New Accounting Pronouncements [Member] \| Previously Reported [Member]
Assets
Current deferred income taxes		74
Deferred charges and other assets, net		2,668
Liabilities
Current deferred income taxes		366
Debt and capital lease obligations, less current portion		7,250
Deferred income taxes		6,768
Adjustments for New Accounting Pronouncements [Member] \| Reclassifications [Member]
Assets
Current deferred income taxes		(74)
Deferred charges and other assets, net		(42)
Liabilities
Current deferred income taxes		(366)
Debt and capital lease obligations, less current portion		(42)
Deferred income taxes		$ 292

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