Income Taxes​ (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) points	Sep. 30, 2020 USD ($) points
Income Tax Disclosure [Abstract]
Effective income tax rate, before discrete items			17.10%	11.70%
Effective Income Tax Rate Reconciliation, Percentage Points | points			3.9	9.3
Effective income tax rate, including discrete items	40.70%	66.70%	18.40%	(12.50%)
Income Tax Expense (Benefit)
Pretax ordinary income (loss) at estimated annual effective tax rate	$ 5	$ 2	$ (75)	$ (5)
Effective Income Tax Reconciliation Change In Estimate From Prior Period Amount	7	51	0	0
Interim period treatment of operational losses in foreign jurisdictions for which no tax benefit is recognized*	$ 0	$ (48)	$ (2)	$ 1
Discrete items	(1)	5	(4)	9
Provision (Benefit) for income taxes	$ 11	$ 10	$ (81)	$ 5