Accumulated Other Comprehensive Loss - Changes in accumulated other comprehensive loss (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 17.7						$ 17.7		$ 19.7
Changes in accumulated other comprehensive loss
Other comprehensive income, net of tax, before reclassifications							14.4
Amounts reclassified from AOCI, net of tax benefit of $8.5, $—, and $8.5							(23.6)
Reclassification from AOCI, Current Period, Tax							8.5
Less: noncontrolling interest	(0.2)	$ (5.0)	$ 14.4	$ (10.3)	$ (5.3)	$ (17.3)	9.2	$ (32.9)
Other comprehensive loss							(2.0)
Unrealized gains/(losses) on derivative financial instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	18.9						18.9		20.9
Changes in accumulated other comprehensive loss
Other comprehensive income, net of tax, before reclassifications							14.4
Amounts reclassified from AOCI, net of tax benefit of $8.5, $—, and $8.5							(23.6)
Reclassification from AOCI, Current Period, Tax							8.5
Other comprehensive loss							(2.0)
Unrealized gains/(losses) on derivative financial instruments | TRIP Holdings [Member]
Changes in accumulated other comprehensive loss
Reclassification from AOCI, Current Period, Tax							13.2
Unrealized gains/(losses) on derivative financial instruments | Parent
Changes in accumulated other comprehensive loss
Reclassification from AOCI, Current Period, Tax							4.4
Net actuarial gains/(losses) of defined benefit plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(1.2)						(1.2)		(1.2)
Changes in accumulated other comprehensive loss
Other comprehensive income, net of tax, before reclassifications							0.0
Amounts reclassified from AOCI, net of tax benefit of $8.5, $—, and $8.5							0.0
Reclassification from AOCI, Current Period, Tax							0.0
Other comprehensive loss							0.0
Accumulated Gain (Loss), Net, Cash Flow Hedge, Noncontrolling Interest [Member]
Changes in accumulated other comprehensive loss
Less: noncontrolling interest							7.2
Noncontrolling Interest [Member]
Changes in accumulated other comprehensive loss
Less: noncontrolling interest	(0.1)	(0.1)	7.4	(0.3)	1.0	(0.2)	7.2
Accumulated other comprehensive income (loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	17.7						$ 17.7		$ 19.7
Changes in accumulated other comprehensive loss
Less: noncontrolling interest	$ (0.1)	$ (4.9)	$ 7.0	$ (10.0)	$ (6.3)	$ (17.1)