Net Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended						9 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2023	Dec. 31, 2022
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 419.2	$ 666.6	$ 666.4	$ 580.3	$ 546.2	$ 507.2	$ 1,752.2	$ 1,633.7
Basic weighted average common shares outstanding (in shares)	540.8			549.2			543.0	551.5
Dilutive effect of stock options and RSUs (in shares)	4.9			4.8			5.0	5.1
Diluted weighted average common shares outstanding (in shares)	546.5			555.4			549.0	558.4
Basic net income per common share (in dollars per share)	$ 0.78			$ 1.06			$ 3.23	$ 2.96
Diluted net income per common share (in dollars per share)	$ 0.77			$ 1.04			$ 3.19	$ 2.93
2015 Senior Convertible Debt
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive effect of Convertible Debt (in shares)	0.2			0.4			0.2	0.7
2015 Senior Convertible Debt | Weighted Average
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Debt instrument, convertible, conversion price (in dollars per share)	$ 28.95			$ 29.52			$ 29.10	$ 29.65
2017 Senior Convertible Debt
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive effect of Convertible Debt (in shares)	0.6			0.9			0.8	1.0
2017 Senior Convertible Debt | Weighted Average
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Debt instrument, convertible, conversion price (in dollars per share)	$ 45.14			$ 46.03			$ 45.38	$ 46.23
2020 Senior Convertible Debt | Weighted Average
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Debt instrument, convertible, conversion price (in dollars per share)	$ 91.78			$ 92.74			$ 92.05	$ 92.91
2017 Junior Convertible Debt
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive effect of Convertible Debt (in shares)	0.0			0.1			0.0	0.1
2017 Junior Convertible Debt | Weighted Average
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Debt instrument, convertible, conversion price (in dollars per share)	$ 0			$ 45.22			$ 44.81	$ 45.42