Restructuring Restructuring Other Related Charges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Charges related to voluntary termination program	$ 18
John F. North III [Member]
Restructuring Cost and Reserve [Line Items]
Other Nonrecurring Expense	5
Michael K. Tucker [Member]
Restructuring Cost and Reserve [Line Items]
Other Nonrecurring Expense	2
Larry D. De Shon [Member]
Restructuring Cost and Reserve [Line Items]
Other Nonrecurring Expense	$ 1	$ 14
Mark J. Servodidio [Member]
Restructuring Cost and Reserve [Line Items]
Other Nonrecurring Expense		$ 4