Debt (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Commercial Paper and Borrowings Under Bank Credit Facilities
Balance	$ 82.2	$ 10.4
Weighted average interest rate	3.23%	4.24%
Outstanding balances of debt obligations and the applicable interest rates
Total debt principal	$ (12,505.6)	$ (8,270.9)
Debt discount, net	(52.5)	(51.6)
Debt adjustment for fair value hedges	(1.4)	(4.0)
Recourse debt	12,451.7	8,215.3
Balance due in 2026	653.3
Second Line of Credit US
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	368.0	350.0
Recourse Fixed Rate Debt Unsecured One [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 350.0	350.0
Interest rate, stated percentage	3.25%
Recourse Fixed Rate Debt Unsecured Two [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 350.0	350.0
Interest rate, stated percentage	5.40%
Recourse Fixed Rate Debt Unsecured Three [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 300.0	300.0
Interest rate, stated percentage	3.85%
Recourse Fixed Rate Debt Unsecured Four [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 300.0	300.0
Interest rate, stated percentage	3.50%
Recourse Fixed Rate Debt Unsecured Five [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 300.0	300.0
Interest rate, stated percentage	4.55%
Recourse Fixed Rate Debt Unsecured Six [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 500.0	500.0
Interest rate, stated percentage	4.70%
Recourse Fixed Rate Debt Unsecured Seven [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 500.0	500.0
Interest rate, stated percentage	4.00%
Recourse Fixed Rate Debt Unsecured Eight [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 400.0	400.0
Interest rate, stated percentage	1.90%
Recourse Fixed Rate Debt Unsecured Nine [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 400.0	400.0
Interest rate, stated percentage	3.50%
Recourse Fixed Rate Debt Unsecured Ten [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 400.0	400.0
Interest rate, stated percentage	4.90%
Recourse Fixed Rate Debt Unsecured Eleven [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 400.0	400.0
Interest rate, stated percentage	5.45%
Recourse Fixed Rate Debt Unsecured Twelve [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 500.0	500.0
Interest rate, stated percentage	6.05%
Recourse Fixed Rate Debt Unsecured Fourteen [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 700.0	0.0
Interest rate, stated percentage	5.50%
Recourse Fixed Rate Debt Unsecured Fifteen [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 300.0	300.0
Interest rate, stated percentage	5.20%
Recourse Fixed Rate Debt Unsecured Sixteen [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 250.0	250.0
Interest rate, stated percentage	4.50%
Recourse Fixed Rate Debt Unsecured Seventeen [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 550.0	550.0
Interest rate, stated percentage	3.10%
Recourse Fixed Rate Debt Unsecured Eighteen
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 400.0	400.0
Interest rate, stated percentage	6.05%
Recourse Fixed Rate Debt Unsecured Nineteen [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 500.0	0.0
Interest rate, stated percentage	6.05%
Recourse Fixed Rate Debt Unsecured Twenty [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 0.0	300.0
Interest rate, stated percentage	3.25%
Recourse Fixed Rate Debt Unsecured Twenty One [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 27.0	23.8
Interest rate, stated percentage	0.90%
Recourse Fixed Rate Debt Unsecured Twenty Two [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 44.0	38.8
Interest rate, stated percentage	5.23%
Recourse Fixed Rate Debt Unsecured Twenty Three [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 88.1	77.7
Interest rate, stated percentage	1.07%
Recourse Fixed Rate Debt Unsecured Twenty Four [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 41.1	36.2
Interest rate, stated percentage	4.37%
Recourse Fixed Rate Debt Unsecured Twenty Five [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 61.1	53.8
Interest rate, stated percentage	1.17%
Recourse Fixed Rate Debt Unsecured Twenty Seven [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 135.1	0.0
Interest rate, stated percentage	3.24%
Recourse Fixed Rate Debt Unsecured Twenty Eight [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 88.1	77.7
Interest rate, stated percentage	1.56%
Recourse Fixed Rate Debt Unsecured Thirty Three [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 45.6	47.9
Balance due in 2026	$ 11.4
Recourse Fixed Rate Debt Unsecured Thirty Three [Member] | Minimum [Member]
Outstanding balances of debt obligations and the applicable interest rates
Interest rate, stated percentage	8.39%
Recourse Fixed Rate Debt Unsecured Thirty Three [Member] | Maximum [Member]
Outstanding balances of debt obligations and the applicable interest rates
Interest rate, stated percentage	8.83%
Recourse Fixed Rate Debt [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 8,675.1	7,663.4
Recourse Floating Rate Debt Unsecured One [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 50.0	50.0
Interest rate, stated percentage	5.06%
Recourse Floating Rate Debt Unsecured Two [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 125.0	100.0
Interest rate, stated percentage	5.26%
Recourse Floating Rate Debt Unsecured Three [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 50.0	50.0
Interest rate, stated percentage	5.90%
Recourse Floating Rate Debt Unsecured Four [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 2,959.0	0.0
Interest rate, stated percentage	5.02%
Total Recourse Floating Rate Debt [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 3,830.5	607.5
Total Recourse Floating Rate Debt [Member] | Rail North America [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	3,184.0	200.0
Recourse Floating Rate Debt Unsecured Five [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 132.7	125.3
Interest rate, stated percentage	3.56%
Recourse Floating Rate Debt Unsecured Six [Member]
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 129.2	113.9
Interest rate, stated percentage	3.51%
UNITED STATES
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 7,800.0	6,900.0
INDIA
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	138.0	144.9
Recourse Fixed Rate Debt Unsecured Twenty Six
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 88.1	0.0
Interest rate, stated percentage	3.21%
Recourse Fixed Rate Debt Unsecured Twenty Nine
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 117.5	103.5
Interest rate, stated percentage	3.62%
Recourse Fixed Rate Debt Unsecured Thirty
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 47.0	0.0
Interest rate, stated percentage	3.88%
Recourse Fixed Rate Debt Unsecured Thirty One
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 0.0	103.5
Interest rate, stated percentage	1.00%
Recourse Fixed Rate Debt Unsecured Thirty Two
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 0.0	103.5
Interest rate, stated percentage	1.13%
Recourse Fixed Rate Debt Unsecured Thirty Four
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 25.6	26.9
Recourse Fixed Rate Debt Unsecured Thirty Four | Minimum [Member]
Outstanding balances of debt obligations and the applicable interest rates
Interest rate, stated percentage	8.13%
Recourse Fixed Rate Debt Unsecured Thirty Four | Maximum [Member]
Outstanding balances of debt obligations and the applicable interest rates
Interest rate, stated percentage	8.53%
Recourse Fixed Rate Debt Unsecured Thirty Six
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 22.3	23.4
Recourse Fixed Rate Debt Unsecured Thirty Six | Minimum [Member]
Outstanding balances of debt obligations and the applicable interest rates
Interest rate, stated percentage	8.51%
Recourse Fixed Rate Debt Unsecured Thirty Six | Maximum [Member]
Outstanding balances of debt obligations and the applicable interest rates
Interest rate, stated percentage	8.80%
Recourse Floating Rate Debt Unsecured Seven
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 99.8	0.0
Interest rate, stated percentage	3.16%
Recourse Fixed Rate Debt Unsecured Thirteen
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 400.0	400.0
Interest rate, stated percentage	6.90%
Recourse Fixed Rate Debt Unsecured Thirty Five
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 44.5	46.7
Recourse Fixed Rate Debt Unsecured Thirty Five | Minimum [Member]
Outstanding balances of debt obligations and the applicable interest rates
Interest rate, stated percentage	8.43%
Recourse Fixed Rate Debt Unsecured Thirty Five | Maximum [Member]
Outstanding balances of debt obligations and the applicable interest rates
Interest rate, stated percentage	8.94%
Recourse Floating Rate Debt Unsecured eight
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 88.1	77.7
Interest rate, stated percentage	3.71%
Recourse Floating Rate Debt Unsecured Nine
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 44.0	38.8
Interest rate, stated percentage	4.40%
Recourse Floating Rate Debt Unsecured Ten
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 58.7	51.8
Interest rate, stated percentage	3.85%
Recourse Floating Rate Debt Unsecured Eleven
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 94.0	0.0
Interest rate, stated percentage	3.49%
Recourse Fixed Rate Debt Unsecured, Europe
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	$ 737.1	618.5
Recourse Floating Rate Debt Unsecured, Europe
Outstanding balances of debt obligations and the applicable interest rates
Total Debt	646.5	407.5
Line of Credit US
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 632.0	$ 600.0