Other Income (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Other income	$ 17.1	$ 16.4	$ 32.4	$ 34.2
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Other income	14.3		26.2
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Other income	2.8		6.2
Third Party Providers [Member]
Disaggregation of Revenue [Line Items]
Other income	14.0		25.6
Dealers [Member]
Disaggregation of Revenue [Line Items]
Other income	3.1		6.8
Ancillary Product Profit Sharing [Member]
Disaggregation of Revenue [Line Items]
Other income	9.1	12.9	16.6	27.6
Ancillary Product Profit Sharing [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Other income	9.1		16.6
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	9.1		16.6
Ancillary Product Profit Sharing [Member] | Dealers [Member]
Disaggregation of Revenue [Line Items]
Other income	0.0		0.0
Remarketing Fees [Member]
Disaggregation of Revenue [Line Items]
Other income	2.7	1.9	5.7	3.9
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	2.7		5.7
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	2.7		5.7
Interest [Member]
Disaggregation of Revenue [Line Items]
Other income	4.9	0.7	9.0	1.0
Interest [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Other income	4.9		9.0
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	4.9		9.0
Interest [Member] | Dealers [Member]
Disaggregation of Revenue [Line Items]
Other income	0.0		0.0
Other [Member]
Disaggregation of Revenue [Line Items]
Other income	0.4	$ 0.9	1.1	$ 1.7
Other [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Other income	0.3		0.6
Other [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Other income	0.1		0.5
Other [Member] | Third Party Providers [Member]
Disaggregation of Revenue [Line Items]
Other income	0.0		0.0
Other [Member] | Dealers [Member]
Disaggregation of Revenue [Line Items]
Other income	$ 0.4		$ 1.1