Consolidated Statements of Equity - USD ($) $ in Millions	Total	Total common shareholders' equity	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)	Preferred stock of subsidiary	Noncontrolling interests
Balance at Dec. 31, 2019	$ 10,254.6	$ 10,113.4	$ 3.2	$ 4,186.6	$ 5,927.7	$ (4.1)	$ 30.4	$ 110.8
Equity
Net income attributed to common shareholders	1,199.9	1,199.9	0.0	0.0	1,199.9	0.0	0.0	0.0
Net income (loss) attributed to noncontrolling interests	0.3	0.0	0.0	0.0	0.0	0.0	0.0	0.3
Other comprehensive income (loss)	(2.7)	(2.7)	0.0	0.0	0.0	(2.7)	0.0	0.0
Common stock dividends	(798.0)	(798.0)	0.0	0.0	(798.0)	0.0	0.0	0.0
Exercise of stock options	43.8	43.8	0.0	43.8	0.0	0.0	0.0	0.0
Purchase of common stock	(99.2)	(99.2)	0.0	(99.2)	0.0	0.0	0.0	0.0
Purchase of additional ownership interest in Upstream from noncontrolling interest	(31.0)	0.0	0.0	0.0	0.0	0.0	0.0	(31.0)
Acquisition of noncontrolling interests	85.0	0.0	0.0	0.0	0.0	0.0	0.0	85.0
Distributions to noncontrolling interests	(2.7)	0.0	0.0	0.0	0.0	0.0	0.0	(2.7)
Stock-based compensation and other	12.5	12.5	0.0	12.5	0.0	0.0	0.0	0.0
Balance at Dec. 31, 2020	10,662.5	10,469.7	3.2	4,143.7	6,329.6	(6.8)	30.4	162.4
Equity
Net income attributed to common shareholders	1,300.3	1,300.3	0.0	0.0	1,300.3	0.0	0.0	0.0
Net income (loss) attributed to noncontrolling interests	(3.0)	0.0	0.0	0.0	0.0	0.0	0.0	(3.0)
Other comprehensive income (loss)	3.6	3.6	0.0	0.0	0.0	3.6	0.0	0.0
Common stock dividends	(854.8)	(854.8)	0.0	0.0	(854.8)	0.0	0.0	0.0
Exercise of stock options	15.7	15.7	0.0	15.7	0.0	0.0	0.0	0.0
Purchase of common stock	(33.1)	(33.1)	0.0	(33.1)	0.0	0.0	0.0	0.0
Acquisition of noncontrolling interests	6.3	0.0	0.0	0.0	0.0	0.0	0.0	6.3
Capital contributions from noncontrolling interest	7.6	0.0	0.0	0.0	0.0	0.0	0.0	7.6
Distributions to noncontrolling interests	(4.1)	0.0	0.0	0.0	0.0	0.0	0.0	(4.1)
Stock-based compensation and other	12.3	11.8	0.0	11.8	0.0	0.0	0.0	0.5
Balance at Dec. 31, 2021	11,113.3	10,913.2	3.2	4,138.1	6,775.1	(3.2)	30.4	169.7
Equity
Net income attributed to common shareholders	1,408.1	1,408.1	0.0	0.0	1,408.1	0.0	0.0	0.0
Net income (loss) attributed to noncontrolling interests	0.4	0.0	0.0	0.0	0.0	0.0	0.0	0.4
Other comprehensive income (loss)	(3.6)	(3.6)	0.0	0.0	0.0	(3.6)	0.0	0.0
Common stock dividends	(917.9)	(917.9)	0.0	0.0	(917.9)	0.0	0.0	0.0
Exercise of stock options	33.6	33.6	0.0	33.6	0.0	0.0	0.0	0.0
Purchase of common stock	(69.2)	(69.2)	0.0	(69.2)	0.0	0.0	0.0	0.0
Acquisition of noncontrolling interests	42.5	0.0	0.0	0.0	0.0	0.0	0.0	42.5
Capital contributions from noncontrolling interest	1.1	0.0	0.0	0.0	0.0	0.0	0.0	1.1
Distributions to noncontrolling interests	(4.3)	0.0	0.0	0.0	0.0	0.0	0.0	(4.3)
Stock-based compensation and other	12.6	12.7	0.0	12.7	0.0	0.0	0.0	(0.1)
Balance at Dec. 31, 2022	$ 11,616.6	$ 11,376.9	$ 3.2	$ 4,115.2	$ 7,265.3	$ (6.8)	$ 30.4	$ 209.3