Selected Quarterly Financial Data (Schedule Of Selected Quarterly Financial Data) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Data [Abstract]
Interest income	$ 447.7	$ 454.0	$ 478.2	$ 455.7	$ 474.1	$ 475.7	$ 478.7	$ 482.9	$ 1,835.6	$ 1,911.5	$ 1,445.2
Interest expense (benefit)	168.7	176.7	209.2	163.1	178.3	188.2	191.6	195.0	717.7	753.2	731.4
Provision for credit losses	30.4	30.1	4.4	49.7	36.7	45.1	23.3	89.5	114.6	194.7	158.6
Rental income on operating leases	252.6	252.3	251.2	251.3	252.2	254.3	261.0	264.1	1,007.4	1,031.6	1,018.1
Other non-interest income	137.2	63.3	84.6	79.1	(117.6)	83.6	99.8	84.8	364.2	150.6	149.6
Depreciation on operating lease equipment	74.3	71.1	77.4	73.5	69.8	66.9	63.1	61.3	296.3	261.1	229.2
Maintenance and other operating lease expenses	57.9	57.9	53.3	53.8	57.5	56.6	50.6	48.9	222.9	213.6	185.1
Goodwill impairment	255.6	0.0	0.0	0.0	354.2	0.0	0.0	0.0	255.6	354.2	0.0
Operating expenses	304.0	277.3	295.6	311.6	341.3	302.9	309.3	330.1	1,188.5	1,283.5	1,121.1
Loss on debt extinguishments and deposit redemptions	1.7	53.5	164.8	0.0	3.3	5.2	2.4	1.6	220.0	12.5	1.5
Continuing operations (benefit) / provision	27.7	(119.8)	(31.9)	56.2	(6.6)	54.5	111.2	44.4	(67.8)	203.5	(538.0)
Income (loss) from discontinued operations, net of taxes	(5.2)	(3.2)	115.5	101.7	(716.7)	37.3	(71.0)	85.0	90.2	(665.4)	310.0
Net income (loss)	(88.0)	219.6	156.7	179.9	(1,142.5)	131.5	17.0	146.0	468.2	(848.0)	1,034.0
Net Income (loss) applicable to common shareholders	(97.8)	219.6	156.7	179.9	(1,142.5)	131.5	17.0	146.0	458.4	(848.0)	1,034.1
Income (loss) from continuing operations applicable to common shareholders	$ (92.6)	$ 222.8	$ 41.2	$ 78.2	$ (425.8)	$ 94.2	$ 88.0	$ 61.0	$ 249.6	$ (182.6)	$ 724.1
Net (loss) income per diluted share (in dollars per share)	$ (0.74)	$ 1.61	$ 0.85	$ 0.88	$ (5.65)	$ 0.65	$ 0.08	$ 0.72	$ 2.80	$ (4.20)	$ 5.55