Other Income (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Other income	$ 16.1	$ 23.3	$ 48.5	$ 57.5
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Other income	13.3		39.5
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Other income	2.8		9.0
Third Party Providers [Member]
Disaggregation of Revenue [Line Items]
Other income	13.2		38.8
Dealers [Member]
Disaggregation of Revenue [Line Items]
Other income	2.9		9.7
Ancillary Product Profit Sharing [Member]
Disaggregation of Revenue [Line Items]
Other income	7.8	13.7	24.4	41.3
Ancillary Product Profit Sharing [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Other income	7.8		24.4
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	7.8		24.4
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	5.3	1.9	14.3	2.9
Interest [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Other income	5.3		14.3
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	5.3		14.3
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	2.5	7.1	8.2	11.0
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	2.5		8.2
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	2.5		8.2
Other [Member]
Disaggregation of Revenue [Line Items]
Other income	0.5	$ 0.6	1.6	$ 2.3
Other [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Other income	0.2		0.8
Other [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Other income	0.3		0.8
Other [Member] | Third Party Providers [Member]
Disaggregation of Revenue [Line Items]
Other income	0.1		0.1
Other [Member] | Dealers [Member]
Disaggregation of Revenue [Line Items]
Other income	$ 0.4		$ 1.5