Supplementary Information Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and Cash Equivalents	$ 5,095	$ 7,250
Cash, Cash Equivalents, and Restricted Cash	5,629	7,808
Other Current Assets [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted Cash	534	558
Successor [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash, Cash Equivalents, and Restricted Cash	$ 5,629	$ 7,808