Basis of Presentation and Significant Accounting Policies (Details) - USD ($) $ in Millions			3 Months Ended
		Jan. 01, 2019	Mar. 31, 2019
Basis of Presentation and Significant Accounting Policies (Textual)
ROU assets for operating leases	[1]		$ 1,430
Topic 842 [Member]
Basis of Presentation and Significant Accounting Policies (Textual)
ROU assets for operating leases		$ 1,300
Topic 842 [Member] | MVP Terminal [Member]
Basis of Presentation and Significant Accounting Policies (Textual)
Derecognition of existing assets under construction related to build-to-suit lease arrangement		$ 539

[1] Includes noncash activity of $1.3 billion for ROU assets for operating leases recorded on January 1, 2019 upon adoption of Topic 842.