Supplementary Information Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Millions		Mar. 31, 2020		Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents		$ 1,963		$ 1,764	$ 1,759
Cash and cash equivalents of discontinued operations	[1]	0		0	2,074
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Total Company		2,340	[2]	2,173	4,313	$ 5,024
Other Current Assets [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted Cash		377		409	438
Restricted cash of discontinued operations	[3]	0		0	42
Continuing Operations [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash, Cash Equivalents, and Restricted Cash, Continuing Operations		$ 2,340		$ 2,173	$ 2,197

[1] Refer to Note 3 - Divestitures and Other Transactions, for additional information.

[2] See page 19 for reconciliation of cash and cash equivalents and restricted cash presented in interim Condensed Consolidated Balance Sheets to total cash, cash equivalents and restricted cash presented in the interim Condensed Consolidated Statements of Cash Flows.

[3] Amount included in other current assets within assets of discontinued operations - current. Refer to Note 3 - Divestitures and Other Transactions, for additional information.