Condensed Consolidated Statements of Changes In Stockholders' Equity (Unaudited) - USD ($) $ in Millions		Cumulative Effect, Period of Adoption, Adjustment [Member] Common Stock [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Additional Paid-in Capital [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Treasury Stock [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] AOCI Attributable to Parent [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Noncontrolling Interest [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Noncontrolling Interest [Member]	Total
Balance (in shares) at Dec. 31, 2019									544,003,038
Balance at Dec. 31, 2019		$ 0.0	$ 0.0	$ 0.0	$ (2.4)	$ 0.0	$ 0.0	$ (2.4)	$ 0.1	$ 2,369.1	$ (3,849.9)	$ 4,228.4	$ (486.9)	$ 0.0	$ 2,260.8
Net income									0.0	0.0	0.0	171.7	0.0	0.0	171.7
Comprehensive loss attributable to noncontrolling interest															0.0
Other comprehensive income									0.0	0.0	0.0	0.0	(171.8)	0.0	(171.8)
Common stock dividend (1)	[1]								0.0	0.0	0.0	(44.3)	0.0	0.0	(44.3)
Treasury stock acquired									0.0	0.0	(173.8)	0.0	0.0	0.0	(173.8)
Stock options exercised									0.0	14.8	4.7	0.0	0.0	0.0	19.5
Stock-based compensation expense									0.0	19.6	0.0	0.0	0.0	0.0	19.6
Other stock issuances									$ 0.0	1.1	0.1	0.0	0.0	0.0	1.2
Balance (in shares) at Mar. 31, 2020									544,003,038
Balance at Mar. 31, 2020									$ 0.1	2,404.6	(4,018.9)	4,353.4	(658.7)	0.0	2,080.5
Balance (in shares) at Dec. 31, 2020									544,003,038
Balance at Dec. 31, 2020									$ 0.1	2,490.9	(4,179.3)	4,762.2	(375.7)	0.0	2,698.2
Net income									0.0	0.0	0.0	168.0	0.0	0.0	168.0
Comprehensive loss attributable to noncontrolling interest, Impact on Equity									0.0	0.0	0.0	0.6	0.0		(0.2)
Comprehensive loss attributable to noncontrolling interest														(0.8)	(0.8)
Investment in noncontrolling interest									0.0	0.0	0.0	0.0	0.0	16.0	16.0
Other comprehensive income									0.0	0.0	0.0	0.0	9.5	0.0	9.5
Common stock dividend (1)	[1]								0.0	0.0	0.0	(46.7)	0.0	0.0	(46.7)
Treasury stock acquired									0.0	0.0	(100.0)	0.0	0.0	0.0	(100.0)
Stock options exercised									0.0	6.1	1.3	0.0	0.0	0.0	7.4
Performance share units lapsed									0.0	(0.6)	0.6	0.0	0.0	0.0	0.0
Restricted stock lapsed									0.0	(0.3)	0.3	0.0	0.0	0.0	0.0
Stock-based compensation expense									0.0	25.4	0.0	0.0	0.0	0.0	25.4
Net share settlement from restricted stock awards									0.0	(7.8)	0.0	0.0	0.0	0.0	(7.8)
Other stock issuances									$ 0.0	1.6	0.1	0.0	0.0	0.0	1.7
Balance (in shares) at Mar. 31, 2021									544,003,038
Balance at Mar. 31, 2021									$ 0.1	$ 2,515.3	$ (4,277.0)	$ 4,884.1	$ (366.2)	$ 15.2	$ 2,771.5

[1] Refer to Note 11. Stockholders' Equity for discussion related to quarterly cash dividends declared per share