Employee Benefit Plans - Narrative (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Common stock authorized under share based payment award plans (in shares)	45		45
Common stock shares available for awards (in shares)	28		28
Unrecognized compensation cost	$ 82		$ 82
Unrecognized compensation cost, period for recognition			2 years 4 months 24 days
Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Vesting period			1 year
Options
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expiration period			10 years
Vesting period			3 years
Stock Appreciation Rights
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expiration period			10 years
Vesting period			3 years
Performance Share Units
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Vesting period			3 years
Performance Share Units | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Vesting period			1 year
Other Postretirement Benefits Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost (credit)	$ 1	$ 1	$ 1	$ 1