Basis of Presentation Basis of Presentation, Uses of Estimates and Significant Accounting Policies (Details) - Accounting Standards Update 2016-02 [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019
New Accounting Pronouncement or Change in Accounting Principle, Description of Transition Method	Cumulative effect upon adoption approach
New Accounting Pronouncement, Transition Guidance Not Significant or Not Practical	Impact is not material
Operating Lease, Right-of-Use Asset		$ 3,300
Operating Lease, Liability, Current		$ 668