Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Stockholders' Equity Attributable to Parent	$ 1,959.8	$ 941.1	$ 962.1	$ 56.6
Net income	192.1	0.0	192.1	0.0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ (67.6)	0.0	0.0	(67.6)
Stock Repurchased and Retired During Period, Shares	128,171
Common shares purchased and retired	$ (5.4)	(5.4)	0.0	0.0
Stock issued during period, new issues (in shares)	19,081
Stock issued during period, RSU (in shares)	241,307
Stock Issued During Period, Value, New Issues	$ 0.0	0.0	0.0	0.0
Non-vested common shares forfeited or canceled	0.0	0.0	0.0	0.0
Stock compensation expense	0.4	0.4	0.0	0.0
Stock compensation expense	8.9	8.9	0.0	0.0
APIC, Share-based Payment Arrangement, Option, Increase for Cost Recognition	$ (101.6)	0.0	(101.6)	0.0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	73,044
Dividends declared (in usd per share)	$ 1.64
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	45,484
Shares tendered in payment of option price and income tax withholding amounts, shares	6,982
Stockholders' Equity Attributable to Parent	$ 1,986.6	945.0	1,052.6	(11.0)
Common Stock, Value, Issued	0.0	0.0	0.0	0.0
Net income	202.2	0.0	202.2	0.0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ (466.1)	0.0	0.0	(466.1)
Stock Repurchased and Retired During Period, Shares	5,040,896
Common shares purchased and retired	$ (199.0)	(199.0)	0.0	0.0
Stock issued during period, new issues (in shares)	46,913,370
Stock issued during period, RSU (in shares)	458,177
Stock Issued During Period, Value, New Issues	$ 1,722.5	1,722.5	0.0	0.0
Non-vested common shares forfeited or canceled	0.0	0.0	0.0	0.0
Stock compensation expense	0.1	0.1	0.0	0.0
Stock compensation expense	9.6	9.6	0.0	0.0
APIC, Share-based Payment Arrangement, Option, Increase for Cost Recognition	$ (182.1)	0.0	(182.1)	0.0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	106,891
Dividends declared (in usd per share)	$ 1.70
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	17,807
Shares tendered in payment of option price and income tax withholding amounts, shares	4,877
Stockholders' Equity Attributable to Parent	$ 3,073.8	2,478.2	1,072.7	(477.1)
Common Stock, Value, Issued	0.0	0.0	0.0	0.0
Net income	257.5	0.0	257.5	0.0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ 120.6	0.0	0.0	120.6
Stock Repurchased and Retired During Period, Shares	1,056,191
Common shares purchased and retired	$ (34.0)	(34.0)	0.0	0.0
Stock issued during period, RSU (in shares)	683,574
Non-vested common shares forfeited or canceled	$ 0.0	0.0	0.0	0.0
Stock compensation expense	4.7	4.7	0.0	0.0
APIC, Share-based Payment Arrangement, Option, Increase for Cost Recognition	$ (195.1)	0.0	(195.1)	0.0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	127,780
Dividends declared (in usd per share)	$ 1.88
Stockholders' Equity Attributable to Parent	$ 3,227.5	2,448.9	1,135.1	(356.5)
Common Stock, Value, Issued	$ 0.0	$ 0.0	$ 0.0	$ 0.0