Supplementary Information Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jun. 01, 2019	Dec. 31, 2018		Dec. 31, 2017	Aug. 31, 2017	Dec. 31, 2016
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and Cash Equivalents	$ 1,764		$ 2,270
Restricted Cash		$ 319
Cash, Cash Equivalents, and Restricted Cash	2,173		2,730
Cash and Cash Equivalents of discontinued operations	0		2,254	[1]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations	2,173		5,024		$ 7,914	$ 4,005	$ 4,548
Other Current Assets [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted Cash	409		460
Disposal group, Including Discontinued Operation, Restricted Cash	$ 0		$ 40	[2]

[1] Refer to Note 5 - Divestitures and Other Transactions, for additional information.

[2] Amount included in other current assets within assets of discontinued operations - current. Refer to Note 5 - Divestitures and Other Transactions, for additional information.