Restructuring and Other Related Charges (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) employee	Sep. 30, 2020 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 5	$ 17	$ 47	$ 89
Number of positions eliminated | employee			120
Voluntary termination | Limited Voluntary Opportunity Plan (“LVOP”)
Restructuring Cost and Reserve [Line Items]
Restructuring expenses			$ 17	18
John F. North
Restructuring Cost and Reserve [Line Items]
Labor and Related Expense		$ 3
Michael K. Tucker
Restructuring Cost and Reserve [Line Items]
Other nonrecurring expense				$ 2