Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [Abstract]

Stock option activity [Text Block]

	Shares (thousands)		Weighted average exercise price		Weighted average remaining contractual life (in years)	Aggregate intrinsic value (in millions)
Outstanding at January 1, 2017	473		$	17.47	0.1	$	10.4
Exercised	(473	)	$	17.47		$	10.4
Outstanding at December 31, 2017	—		$	—	0.0	$	—
Exercised	—		$	—		$	—
Outstanding at December 31, 2018	—		$	—	0.0	$	—
Exercised	—		$	—		$	—
Outstanding at December 31, 2019	—		$	—	0.0	$	—
Options exercisable at December 31, 2019	—		$	—	0.0	$	—

Cash Proceeds Received and Tax Benefit from Share-based Payment Awards [Table Text Block]

	Year Ended December 31,
(in millions)	2019		2018		2017
Proceeds from stock options exercised — gross	$	—	$	—	$	8
Tax benefit	—		—		8
Proceeds from stock options exercised, net of tax	$	—	$	—	$	16

Restricted stock compensation expense [Text Block]

	Year Ended December 31,
(in millions, except per share data)	2019		2018		2017
Restricted stock compensation expense	$	30	$	26	$	27
Restricted stock compensation expense, net of tax	$	23	$	20	$	20

Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block]

	Shares subject to restriction (thousands)		Weighted average grant date fair value
Nonvested at January 1, 2017	1,429		$	44.12
Granted	804		$	40.10
Vested	(521	)	$	56.53
Forfeited	(119	)	$	38.97
Nonvested at December 31, 2017	1,593		$	38.86
Granted	737		$	51.70
Vested	(556	)	$	42.25
Forfeited	(258	)	$	44.51
Nonvested at December 31, 2018	1,516		$	42.97
Granted	1,082		$	41.66
Vested	(724	)	$	36.81
Forfeited	(210	)	$	44.82
Nonvested at December 31, 2019	1,664		$	44.26

Share-based Payment Arrangement, Performance Shares, Activity [Table Text Block]

	Year Ended December 31,
(in millions, except share data)	2019		2018		2017
Expense	$	7	$	18	$	16
Number of shares	315,000		249,000		126,000

A summary of the status of the Company’s nonvested relative revenue growth performance shares at December 31, 2019, 2018 and 2017 is as follows:

	Number of shares (thousands)		Weighted average grant date fair value
Nonvested at January 1, 2017	320		$	38.62
Granted	198		$	40.08
Vested	(156	)	$	38.62
Forfeited	(7	)	$	39.20
Nonvested at December 31, 2017	355		$	39.42
Granted	287		$	50.82
Vested	(166	)	$	38.62
Forfeited	(179	)	$	45.82
Nonvested at December 31, 2018	297		$	47.03
Granted	196		$	41.90
Vested	(160	)	$	40.10
Forfeited	(93	)	$	44.30
Nonvested at December 31, 2019	240		$	48.52

	Number of shares (thousands)		Weighted average grant date fair value
Nonvested at January 1, 2017	410		$	43.99
Granted	201		$	45.57
Forfeited	(256	)	$	61.40
Nonvested at December 31, 2017	355		$	32.35
Granted	287		$	68.38
Forfeited	(345	)	$	38.26
Nonvested at December 31, 2018	297		$	60.35
Granted	196		$	51.52
Vested	(160	)	$	45.78
Forfeited	(93	)	$	55.82
Nonvested at December 31, 2019	240		$	64.61

	Year Ended December 31,
(in millions, except share data)	2019		2018		2017
Expense	$	5	$	9	$	10
Number of shares	—		—		—