Changes in Allowance for Credit Losses by Segment (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at Beginning of Period	$ 328.1	$ 350.8	$ 328.9	$ 357.3
Charge-Offs	(16.2)	(17.2)	(30.6)	(52.6)
Recoveries	13.0	2.2	21.6	16.0
Net (Charge-Offs) Recoveries	(3.2)	(15.0)	(9.0)	(36.6)
Provision for Credit Losses	5.0	10.0	10.0	25.0
Effect of Foreign Exchange Rates				0.1
Balance at End of Period	329.9	345.8	329.9	345.8
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at Beginning of Period	202.0	247.0	211.0	256.7
Charge-Offs	(5.0)	(7.5)	(8.2)	(28.2)
Recoveries	7.5	0.3	11.2	13.1
Net (Charge-Offs) Recoveries	2.5	(7.2)	3.0	(15.1)
Provision for Credit Losses	(8.2)	0.1	(17.7)	(1.8)
Effect of Foreign Exchange Rates				0.1
Balance at End of Period	196.3	239.9	196.3	239.9
Personal
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at Beginning of Period	126.1	103.8	117.9	100.6
Charge-Offs	(11.2)	(9.7)	(22.4)	(24.4)
Recoveries	5.5	1.9	10.4	2.9
Net (Charge-Offs) Recoveries	(5.7)	(7.8)	(12.0)	(21.5)
Provision for Credit Losses	13.2	9.9	27.7	26.8
Balance at End of Period	$ 133.6	$ 105.9	$ 133.6	$ 105.9