Other Income (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Other income	$ 16.2	$ 17.1	$ 33.1	$ 32.4
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Other income	13.0		26.3
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Other income	3.2		6.8
Third Party Providers [Member]
Disaggregation of Revenue [Line Items]
Other income	12.9		26.1
Dealers [Member]
Disaggregation of Revenue [Line Items]
Other income	3.3		7.0
Ancillary Product Profit Sharing [Member]
Disaggregation of Revenue [Line Items]
Other income	6.4	9.1	13.7	16.6
Ancillary Product Profit Sharing [Member] \| Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Other income	6.4		13.7
Ancillary Product Profit Sharing [Member] \| Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Other income	0.0		0.0
Ancillary Product Profit Sharing [Member] \| Third Party Providers [Member]
Disaggregation of Revenue [Line Items]
Other income	6.4		13.7
Ancillary Product Profit Sharing [Member] \| Dealers [Member]
Disaggregation of Revenue [Line Items]
Other income	0.0		0.0
Interest [Member]
Disaggregation of Revenue [Line Items]
Other income	6.4	4.9	12.2	9.0
Interest [Member] \| Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Other income	6.4		12.2
Interest [Member] \| Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Other income	0.0		0.0
Interest [Member] \| Third Party Providers [Member]
Disaggregation of Revenue [Line Items]
Other income	6.4		12.2
Interest [Member] \| Dealers [Member]
Disaggregation of Revenue [Line Items]
Other income	0.0		0.0
Remarketing Fees [Member]
Disaggregation of Revenue [Line Items]
Other income	2.9	2.7	6.2	5.7
Remarketing Fees [Member] \| Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Other income	0.0		0.0
Remarketing Fees [Member] \| Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Other income	2.9		6.2
Remarketing Fees [Member] \| Third Party Providers [Member]
Disaggregation of Revenue [Line Items]
Other income	0.0		0.0
Remarketing Fees [Member] \| Dealers [Member]
Disaggregation of Revenue [Line Items]
Other income	2.9		6.2
Other [Member]
Disaggregation of Revenue [Line Items]
Other income	0.5	$ 0.4	1.0	$ 1.1
Other [Member] \| Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Other income	0.2		0.4
Other [Member] \| Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Other income	0.3		0.6
Other [Member] \| Third Party Providers [Member]
Disaggregation of Revenue [Line Items]
Other income	0.1		0.2
Other [Member] \| Dealers [Member]
Disaggregation of Revenue [Line Items]
Other income	$ 0.4		$ 0.8