Description of Business and Significant Accounting Policies Description of Business and Significant Accounting Policies - Recent Accounting Pronouncements (Details) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Unamortized Debt Issuance Expense	[1]	$ 34	$ 41
Deferred income taxes		582	349
Current deferred tax assets		$ 0	$ 264

[1] In 2015, we adopted ASU 2015-03, Interest - Imputation of Interest: Simplifying the Presentation of Debt Issuance Costs, which requires debt issuance costs previously reported as a deferred charge within other assets to be presented as a direct reduction from the carrying amount of debt, consistent with debt discounts, applied retrospectively for all periods presented. Long-term debt and other assets as of December 31, 2014 were adjusted by approximately $41 million as a result of the adoption of this ASU.