Changes in Total Allowance for Credit Losses by Segment (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at Beginning of Period	$ 323.8	$ 328.1	$ 327.6	$ 328.9
Charge-Offs	(15.6)	(16.2)	(28.2)	(30.6)
Recoveries	7.5	13.0	11.4	21.6
Net (Charge-Offs) Recoveries	(8.1)	(3.2)	(16.8)	(9.0)
Provision for Credit Losses	5.0	5.0	10.0	10.0
Effect of Foreign Exchange Rates			(0.1)
Balance at End of Period	320.7	329.9	320.7	329.9
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at Beginning of Period	187.1	202.0	194.2	211.0
Charge-Offs	(4.3)	(5.0)	(5.2)	(8.2)
Recoveries	4.6	7.5	6.4	11.2
Net (Charge-Offs) Recoveries	0.3	2.5	1.2	3.0
Provision for Credit Losses	(3.3)	(8.2)	(11.2)	(17.7)
Effect of Foreign Exchange Rates			(0.1)
Balance at End of Period	184.1	196.3	184.1	196.3
Personal
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at Beginning of Period	136.7	126.1	133.4	117.9
Charge-Offs	(11.3)	(11.2)	(23.0)	(22.4)
Recoveries	2.9	5.5	5.0	10.4
Net (Charge-Offs) Recoveries	(8.4)	(5.7)	(18.0)	(12.0)
Provision for Credit Losses	8.3	13.2	21.2	27.7
Balance at End of Period	$ 136.6	$ 133.6	$ 136.6	$ 133.6