Non-Interest Expenses (Schedule Of Non-Interest Expenses) (Details) - USD ($) $ 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
Noninterest Expense [Abstract]
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
Operating expenses:
Compensation and benefits									566.3	585.5	549.6
Professional fees									132.3	175.8	135.0
Technology									127.9	133.7	109.2
Insurance									84.7	96.5	61.6
Net occupancy expense									67.8	71.9	49.1
Advertising and marketing									42.2	20.5	30.4
Other									89.6	137.8	114.6
Operating expenses, excluding restructuring costs and intangible asset amortization									1,110.8	1,221.7	1,049.5
Intangible asset amortization									24.7	25.6	13.3
Restructuring costs									53.0	36.2	58.3
Total 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
Goodwill impairment	255.6	0.0	0.0	0.0	354.2	0.0	0.0	0.0	255.6	354.2	0.0
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
Total non-interest expenses									$ 2,183.3	$ 2,124.9	$ 1,536.9