Fair Value of Financial Instruments (Details) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Assets
Notes receivable (a)		$ 34	$ 73
Long-term Debt		19,406	19,620
Liabilities
Debt Instrument, Fair Value Disclosure	[1]	18,566	18,263
Level 2
Liabilities
Debt Instrument, Fair Value Disclosure		11,055	11,028
Level 3
Assets
Notes receivable (a)	[2]	34	73
Liabilities
Debt Instrument, Fair Value Disclosure		7,511	7,235
Carrying Amount
Assets
Notes receivable (a)	[2]	34	73
Long-term Debt	[1]	$ 19,406	$ 19,620

[1] Excludes deferred financing costs, which are recorded as a reduction to long-term debt on the Company's consolidated balance sheets.

[2] Includes the current portion of notes receivable which is recorded in prepayments and other current assets on the Company's consolidated balance sheets.