Changes in Allowance for Credit Losses by Segment (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at Beginning of Period	$ 327.6	$ 328.9
Charge-Offs	(12.6)	(14.4)
Recoveries	3.9	8.6
Net (Charge-Offs) Recoveries	(8.7)	(5.8)
Provision for Credit Losses	5.0	5.0
Effect of Foreign Exchange Rates	(0.1)
Balance at End of Period	323.8	328.1
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at Beginning of Period	194.2	211.0
Charge-Offs	(0.9)	(3.2)
Recoveries	1.8	3.7
Net (Charge-Offs) Recoveries	0.9	0.5
Provision for Credit Losses	(7.9)	(9.5)
Effect of Foreign Exchange Rates	(0.1)
Balance at End of Period	187.1	202.0
Personal
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at Beginning of Period	133.4	117.9
Charge-Offs	(11.7)	(11.2)
Recoveries	2.1	4.9
Net (Charge-Offs) Recoveries	(9.6)	(6.3)
Provision for Credit Losses	12.9	14.5
Balance at End of Period	$ 136.7	$ 126.1