Goodwill and Other Intangible Assets Future Amortization Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Successor [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 315
Predecessor [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense		$ 51
Continuing Operations [Member]
Finite-Lived Intangible Assets [Line Items]
Pre-tax amortization expense, 2018	950
Pre-tax amortization expense, 2019	1,254
Pre-tax amortization expense, 2020	1,244
Pre-tax amortization expense, 2021	1,228
Pre-tax amortization expense, 2022	1,221
Pre-tax amortization expense, 2023	$ 1,207