Note 3. Derivative Instruments and Fair Value Measurements Derivatives - Interest Rate Hedges (Details) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Total stockholders' equity		$ 2,016.0	$ 2,378.9	$ 2,562.0	$ 4,858.0
Designated as Hedging Instrument [Member] | Interest Rate Swap, Expired, 2018 Secured Railcar Equipment Notes [Domain]
Derivative [Line Items]
Derivative, Notional Amount		$ 249.3
Derivative, Average Fixed Interest Rate	[1]	4.41%
Derivative Liability		$ 0.0
Designated as Hedging Instrument [Member] | Interest Rate Swap, Expired, TRIP Holdings Warehouse Loan [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 788.5
Derivative, Average Fixed Interest Rate	[1]	3.60%
Derivative Liability		$ 0.0
Designated as Hedging Instrument [Member] | Interest Rate Swap, Expired, TRIP Master Funding Secured Railcar Equipment Notes [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 34.8
Derivative, Average Fixed Interest Rate	[1]	2.62%
Derivative Liability		$ 0.0
Designated as Hedging Instrument [Member] | Interest Rate Cap [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 169.3
Derivative, Cap Interest Rate		3.00%
Derivative Liability		$ 0.0
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 488.0
Derivative, Average Fixed Interest Rate	[1]	2.66%
Derivative Liability		$ 45.2
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap, Expired, 2018 Secured Railcar Equipment Notes [Domain]
Derivative [Line Items]
Total stockholders' equity		0.8
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap, Expired, TRIP Holdings Warehouse Loan [Member]
Derivative [Line Items]
Total stockholders' equity		1.3
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap, Expired, TRIP Master Funding Secured Railcar Equipment Notes [Member]
Derivative [Line Items]
Total stockholders' equity		0.1
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Designated as Hedging Instrument [Member] | Interest Rate Cap [Member]
Derivative [Line Items]
Total stockholders' equity		(0.5)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Total stockholders' equity		44.7
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Noncontrolling Interest [Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap, Expired, 2018 Secured Railcar Equipment Notes [Domain]
Derivative [Line Items]
Total stockholders' equity		0.0
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Noncontrolling Interest [Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap, Expired, TRIP Holdings Warehouse Loan [Member]
Derivative [Line Items]
Total stockholders' equity		1.8
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Noncontrolling Interest [Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap, Expired, TRIP Master Funding Secured Railcar Equipment Notes [Member]
Derivative [Line Items]
Total stockholders' equity		0.1
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Noncontrolling Interest [Member] | Designated as Hedging Instrument [Member] | Interest Rate Cap [Member]
Derivative [Line Items]
Total stockholders' equity		0.0
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Noncontrolling Interest [Member] | Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Total stockholders' equity		$ 0.0

[1] Weighted average fixed interest rate, except for the interest rate cap on the 2017 promissory notes.