Share-based Payments, PSU's (Details 4) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Weighted Average Grant Date Fair Value
Share-based compensation expense, net of forfeitures, in the fiscal year	$ 31.6	$ 27.5	$ 28.0
The tax benefit related to share-based compensation expense in the fiscal year	6.7	5.8	9.7
Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized	$ 16.6
The average weighted-average period the unrecognized compensation cost will be recognized (years)	1 year
The total fair value of options vested during the fiscal year	$ 0.0	0.0	4.2
Proceeds from Stock Options Exercised	0.0
Tax benefit for tax deductions from options during the fiscal year	$ 2.6	$ 2.3	$ 14.0
TSR Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum retirement age for performance units to vest	60 years
Number Of Trading Days To Calculate Weighted Average Trading Price	30 days
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	3 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Expected volatility (percent)	33.70%	34.30%	34.26%
Expected dividend yield (percent)	0.72%	0.37%	1.97%
Expected term (in years)	3 years	3 years	3 years
Risk-free interest rate (percent)	2.43%	2.42%	1.60%
Shares (in millions)
Granted (in shares)	603,856	401,098	455,740
Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value Per Share, Granted (in usd per share)	$ 25.87	$ 28.09	$ 28.02
Performance Units Cash Settled
Shares (in millions)
Granted (in shares)	203,782
Performance Units
Shares (in millions)
Number of stock units outstanding at beginning of period (shares)	1,300,000
Granted (in shares)	600,000
Issued and canceled (shares)	(500,000)
Number of stock units outstanding at end of period (shares)	1,400,000	1,300,000
Weighted Average Grant Date Fair Value
Weighted-average grant date fair value per share - stock unit awards outstanding, beginning of period (in usd per share)	$ 33.26
Weighted Average Grant Date Fair Value Per Share, Granted (in usd per share)	25.87
Issued and canceled (in usd per share)	27.83
Weighted-average grant date fair value per share - stock unit awards outstanding, end of period (in usd per share)	$ 27.13	$ 33.26