Short-Term Borrowings, Long-Term Debt and Available Credit Facilities Debt Extinguishment (Details) - Successor [Member] - USD ($) $ in Millions		1 Months Ended	3 Months Ended	4 Months Ended	12 Months Ended
		Dec. 11, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Nov. 13, 2018
Debt Instrument [Line Items]
Loss on Extinguishment of Debt			$ 81	$ 0	$ 81
Loans Payable [Member] | Tender Notes [Member]
Debt Instrument [Line Items]
Tender Offer for Debt Securities	[1]					$ 6,200
Extinguishment of Debt, Amount		$ 4,409
Repayments of Long-term Debt, including breakage fees and all applicable accrued and unpaid interest		4,849
Loss on Extinguishment of Debt		$ 81

[1] See discussion of debt extinguishment that follows.