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Stock-Based Compensation (Restricted Stock Units) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 02, 2020
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested, shares, beginning balance	1,700,000
Nonvested, weighted-average grant date fair value, beginning balance (in dollars per share)	$ 40.56
Granted, shares	900,000
Granted, weighted-average grant date fair value (in dollars per share)	$ 44.28	$ 35.51	$ 49.16
Vested, shares	(500,000)
Vested, weighted-average grant date fair value (in dollars per share)	$ 42.40
Forfeited, shares	(200,000)
Forfeited, weighted-average grant date fair value (in dollars per share)	$ 44.21
Nonvested, shares, ending balance	1,900,000	1,700,000
Nonvested, weighted-average grant date fair value, ending balance (in dollars per share)	$ 41.36	$ 40.56
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Granted, weighted-average grant date fair value (in dollars per share)	$ 44.28	$ 35.51	$ 49.16
Total fair value of RSU's vested	$ 23.2	$ 9.0	$ 7.3
Director [Member] | Restricted Stock Units (RSUs) [Member] | Non-Employee Director Equity Plan 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock units granted to each non-employee director				5,110
Employee [Member] | Employee Equity and Incentive Plan 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Measurement Period Performance-Based Restricted Stock Units	1 year
Employee [Member] | Restricted Stock Units (RSUs) [Member] | Employee Equity and Incentive Plan 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Granted, shares	800,000
Employee [Member] | Time-based Restricted Stock Units [Member] | Employee Equity and Incentive Plan 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	4 years
Employee [Member] | Performance-based Restricted Stock Units Graded Vesting [Member] | Employee Equity and Incentive Plan 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	4 years
Employee [Member] | Performance-based Restricted Stock Units Cliff Vesting [Member] | Employee Equity and Incentive Plan 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
Measurement Period Additional Performance Metric Selected Performance-Based Restricted Stock Units	3 years

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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