Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 1,144.3	$ 1,280.6	$ 1,314.8	$ 1,071.9	$ 1,077.3	$ 1,181.4	$ 1,236.1	$ 984.7	$ 4,811.6	$ 4,479.5	$ 3,750.8
Gross margin	308.7	380.2	394.2	288.6	278.8	314.3	332.2	249.4	1,371.7	1,174.7
Operating Income (Loss)	141.3	191.0	207.2	114.7	114.6	140.0	159.7	94.7	654.2	509.0	464.0
Income from continuing operations	104.0	139.3	153.0	77.4	89.1	96.9	114.7	57.9	473.7	358.6	340.6
Income (loss) from discontinued operations	(1.4)	(1.4)	(0.1)	2.0	(1.0)	2.8	(1.0)	251.7	(0.9)	252.5	$ 24.9
Net income	$ 102.6	$ 137.9	$ 152.9	$ 79.4	$ 88.1	$ 99.7	$ 113.7	$ 309.6	$ 472.8	$ 611.1
Basic earnings per share:
Income from continuing operations (in dollars per share)	$ 1.84	$ 2.45	$ 2.68	$ 1.34	$ 1.50	$ 1.61	$ 1.88	$ 0.93	$ 8.30	$ 5.92	$ 5.36
Income (loss) from discontinued operations (in dollars per share)	(0.03)	(0.02)	0	0.03	(0.02)	0.05	(0.02)	4.05	(0.02)	4.17	0.39
Basic earnings per share (in dollars per share)	1.81	2.43	2.68	1.37	1.48	1.66	1.86	4.98	8.28	10.09	5.75
Diluted earnings per share:
Income from continuing operations (in dollars per share)	1.81	2.42	2.65	1.33	1.49	1.59	1.87	0.92	8.21	5.88	5.32
Income (loss) from discontinued operations (in dollars per share)	(0.03)	(0.02)	0	0.03	(0.02)	0.05	(0.02)	4.02	(0.02)	4.14	0.39
Diluted earnings per share (in dollars per share)	$ 1.78	$ 2.40	$ 2.65	$ 1.36	$ 1.47	$ 1.64	$ 1.85	$ 4.94	$ 8.19	$ 10.02	$ 5.71