Severance (Details) - Severance - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Restructuring reserve [Roll Forward]
Balance at the beginning of the period	$ 103	$ 89
Accrued to expense	3	151
Payments, net	(70)	(137)
Balance at the end of the period	$ 36	$ 103