Income Taxes Level 4 (Details) - Unrecognized Tax Benefits - USD ($) $ in Millions	6 Months Ended			12 Months Ended
	Dec. 31, 2019		Jun. 30, 2019	Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018	Jul. 01, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$ 133	[1]	$ 94	$ 130	[1]	$ 94
Additions based on tax positions related to the current year	2		41	4
Additions for tax positions of prior years	0		5	14
Reductions for tax positions of prior years	(3)		(6)	(20)
Settlements	(4)		0	(1)
Foreign currency translation	2		1	2
Balance at end of period(1)	130	[1]		129	[1]	130	[1]	$ 94
Unrecognized Tax Benefits, Period Increase (Decrease)				10		1
Income Tax Examination, Penalties Expense	2		3	9				$ 3
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	56			56		56			$ 54
Discontinued Operations
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period				5
Balance at end of period(1)	$ 5		$ 11	6		$ 5
Maximum [Member]
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Amount of Unrecognized Tax Benefits Expected to Be Recognized within the Next 12 Months				$ 15

[1] Includes unrecognized tax benefits of $6, $5, and $11 for the year ended December 31, 2020, the Successor period July 2, 2019 through December 31, 2019 and the Predecessor period January 1, 2019 through July 1, 2019 associated with the Held for Sale business.