Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net income (loss)	$ 364.3	$ 235.9	$ 1,252.2	$ 937.0
Subtract:
Net income (loss) attributable to noncontrolling interest	4.4	(0.1)	13.4	13.8
Total	$ 359.9	$ 236.0	$ 1,238.8	$ 923.2
Weighted-average shares outstanding:
Basic	268.0	274.8	270.7	274.7
Dilutive effects:
Diluted	271.9	276.8	274.4	276.4
Net income (loss) per common share:
Basic	$ 1.34	$ 0.86	$ 4.58	$ 3.36
Diluted	$ 1.32	$ 0.85	$ 4.51	$ 3.34
Nonqualified Stock Options
Dilutive effects:
Stock-based compensation awards	1.3	0.4	1.2	0.3
Restricted Stock Units
Dilutive effects:
Stock-based compensation awards	2.2	1.5	2.0	1.3
Performance Share Awards
Dilutive effects:
Stock-based compensation awards	0.4	0.1	0.5	0.1