Basis of Presentation and Significant Accounting Policies Basis of Presentation and Significant Accounting Policies Debt Issuance Costs Reclassifications Table (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other long-term assets	$ 277	$ 290
Long-term debt, net	$ 9,938	10,311
Accounting Standards Update 2015-03 [Member] | Other Noncurrent Assets [Member] | Scenario, Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other long-term assets		333
Accounting Standards Update 2015-03 [Member] | Other Noncurrent Assets [Member] | Restatement Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other long-term assets		(43)
Accounting Standards Update 2015-03 [Member] | Other Noncurrent Liabilities [Member] | Scenario, Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Long-term debt, net		10,354
Accounting Standards Update 2015-03 [Member] | Other Noncurrent Liabilities [Member] | Restatement Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Long-term debt, net		$ (43)