Debt - Long-term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Long-term debt
Total long-term debt	$ 9,226.0	$ 9,476.7	$ 9,591.6
Less amounts due within one year	1,049.2	1,098.8	0.6
Long-term debt	8,176.8	8,377.9	9,591.0
Capitalized debt issuance costs	48.6	49.3	57.3
Debt discount	$ 26.0	25.2	25.7
3.45% Senior Notes | Senior Notes
Long-term debt
Interest rate	3.45%
Total long-term debt	$ 1,495.7	1,493.9	1,492.1
4.50% Senior Notes | Senior Notes
Long-term debt
Interest rate	4.50%
Total long-term debt	$ 1,233.7	1,233.0	1,232.3
2.95% Senior Notes | Senior Notes
Long-term debt
Interest rate	2.95%
Total long-term debt	$ 795.5	794.6	793.6
3.80% Senior Notes | Senior Notes
Long-term debt
Interest rate	3.80%
Total long-term debt	$ 543.7	543.6	543.2
2.30% Senior Notes | Senior Notes
Long-term debt
Interest rate	2.30%
Total long-term debt	$ 497.6	497.1	496.7
2.20% Senior Notes | Senior Notes
Long-term debt
Interest rate	2.20%
Total long-term debt	$ 495.5	494.8	494.2
3.30% Senior Notes | Senior Notes
Long-term debt
Interest rate	3.30%
Total long-term debt	$ 494.6	494.3	494.1
2.90% Senior Notes | Senior Notes
Long-term debt
Interest rate	2.90%
Total long-term debt	$ 492.1	491.9	491.5
4.80% Senior Notes | Senior Notes
Long-term debt
Interest rate	4.80%
Total long-term debt	$ 445.0	0.0	0.0
3.45% Senior Notes | Senior Notes
Long-term debt
Interest rate	3.45%
Total long-term debt	$ 399.8	399.4	399.1
4.25% Senior Notes | Senior Notes
Long-term debt
Interest rate	4.25%
Total long-term debt	$ 399.5	398.6	397.7
4.55% Senior Notes | Senior Notes
Long-term debt
Interest rate	4.55%
Total long-term debt	$ 395.4	395.2	395.0
4.55% Senior Notes | Senior Notes
Long-term debt
Interest rate	4.55%
Total long-term debt	$ 397.6	0.0	0.0
3.95% Senior Notes | Senior Notes
Long-term debt
Interest rate	3.95%
Total long-term debt	$ 351.6	353.1	354.7
4.00% Senior Notes | Senior Notes
Long-term debt
Interest rate	4.00%
Total long-term debt	$ 297.2	297.0	296.9
3.30% Senior Notes | Senior Notes
Long-term debt
Interest rate	3.30%
Total long-term debt	$ 250.0	249.9	249.8
4.40% Senior Notes | Senior Notes
Long-term debt
Interest rate	4.40%
Total long-term debt	$ 241.3	240.9	240.5
0.53% to 8.00% Promissory Notes | Unsecured Debt
Long-term debt
Total long-term debt	$ 0.2	0.9	1.6
0.53% to 8.00% Promissory Notes | Unsecured Debt | Minimum
Long-term debt
Interest rate	0.53%
0.53% to 8.00% Promissory Notes | Unsecured Debt | Maximum
Long-term debt
Interest rate	8.00%
4.05% Senior Notes | Senior Notes
Long-term debt
Interest rate	4.05%
Total long-term debt	$ 0.0	598.8	596.9
3.125% Senior Notes | Senior Notes
Long-term debt
Interest rate	3.125%
Total long-term debt	$ 0.0	$ 499.7	499.0
7.375% Debentures | Unsecured Debt
Long-term debt
Interest rate	7.375%	7.38%
Total long-term debt	$ 0.0	$ 0.0	119.2
7.45% Debentures | Unsecured Debt
Long-term debt
Interest rate	7.45%	7.45%
Total long-term debt	$ 0.0	$ 0.0	$ 3.5