Stock Based Compensation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Plan Modification, Incremental Cost	$ 2
Document Period End Date	Mar. 31, 2020
Status of nonvested restricted stock
Performance share compensation expense	$ 3	$ 2
Net impact due to stock awards modification	0	2
Restricted Stock [Member]
Restricted stock compensation expense
Restricted stock compensation expense	7
Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount	$ 51
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	2 years
Status of nonvested restricted stock
Nonvested shares subject to restriction, Beginning Balance	1,664,000
Nonvested shares subject to restriction, weighted average exercise price	$ 44.26
Restricted shares granted to employees	766,205
Granted shares subject to restriction, weighted average exercise price	$ 34.05
Shares subject to restriction, Vested	(466,000)
Vested shares subject to restriction, weighted average exercise price	$ 46.00
Shares subject to restriction, Forfeited	(9,000)
Forfeited shares subject to restriction, weighted average exercise price	$ 42.23
Nonvested shares subject to restriction, Ending Balance	1,955,000
Nonvested shares subject to restriction, weighted average exercise price	$ 39.87
Performance Shares [Member]
Status of nonvested restricted stock
Nonvested shares subject to restriction, Beginning Balance	240,000
Nonvested shares subject to restriction, weighted average exercise price	$ 64.61
Restricted shares granted to employees	142,000
Granted shares subject to restriction, weighted average exercise price	$ 28.55
Shares subject to restriction, Vested	0
Vested shares subject to restriction, weighted average exercise price	$ 0
Shares subject to restriction, Forfeited	0
Forfeited shares subject to restriction, weighted average exercise price	$ 0
Nonvested shares subject to restriction, Ending Balance	382,000
Nonvested shares subject to restriction, weighted average exercise price	$ 48.02
Performance share compensation expense	$ 1	3
Adjusted Earnings Per Share Performance Share Plan [Domain]
Status of nonvested restricted stock
Nonvested shares subject to restriction, Beginning Balance	0
Nonvested shares subject to restriction, weighted average exercise price	$ 0
Restricted shares granted to employees	115,000
Granted shares subject to restriction, weighted average exercise price	$ 34.11
Shares subject to restriction, Vested	0
Vested shares subject to restriction, weighted average exercise price	$ 0
Shares subject to restriction, Forfeited	0
Forfeited shares subject to restriction, weighted average exercise price	$ 0
Nonvested shares subject to restriction, Ending Balance	115,000
Nonvested shares subject to restriction, weighted average exercise price	$ 34.11
Relative Revenue Growth Performance Share Plans [Member]
Status of nonvested restricted stock
Nonvested shares subject to restriction, Beginning Balance	240,000
Nonvested shares subject to restriction, weighted average exercise price	$ 48.52
Restricted shares granted to employees	142,000
Granted shares subject to restriction, weighted average exercise price	$ 34.11
Shares subject to restriction, Vested	0
Vested shares subject to restriction, weighted average exercise price	$ 0
Shares subject to restriction, Forfeited	0
Forfeited shares subject to restriction, weighted average exercise price	$ 0
Nonvested shares subject to restriction, Ending Balance	382,000
Nonvested shares subject to restriction, weighted average exercise price	$ 41.54
Performance share compensation expense	$ 2	$ (1)
2018 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	7,000,000
Number of shares available for grant	5,000,000
First Half Vested | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of awards vested	50.00%
Vesting period	2 years
Second Half Vested | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years