Basis of Presentation ASUs Implemented (Details) - USD ($) $ in Millions		3 Months Ended
	Jan. 01, 2019	Mar. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease, Practical Expedients, Package [true false]		true
Operating lease, right-of-use assets, other long-term assets [Member] | Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 271
Operating lease, liability, other long-term liabilities [Member] | Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 278