Basis of Presentation and Summary of Significant Accounting Policies (Narrative, Recent Financial Accounting Standards) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Current deferred tax assets	$ 0		$ (22)
Current deferred tax liabilities	$ 0		$ (1,066)
New accounting pronouncement, early adoption, effect
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Current deferred tax assets		$ 20
Current deferred tax liabilities		$ 1,100