Financial Guarantees (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012
Guarantor Obligations [Line Items]
Guarantee Obligations Maximum Potential Payment	114.0
Guarantee Liability Carrying Amount	13.0
Guarantees on the residual values of leased properties
Guarantor Obligations [Line Items]
Guarantee Obligations Maximum Potential Payment	26.9
Guarantee Liability Carrying Amount	0
Guarantees on the residual values of leased properties | Minimum
Guarantor Obligations [Line Items]
Guarantee Obligation Term	1 year
Guarantees on the residual values of leased properties | Maximum
Guarantor Obligations [Line Items]
Guarantee Obligation Term	4 years
Standby letters of credit
Guarantor Obligations [Line Items]
Guarantee Obligations Maximum Potential Payment	69.8
Guarantee Liability Carrying Amount	0
Standby letters of credit | Maximum
Guarantor Obligations [Line Items]
Guarantee Obligation Term	3 years
Commercial customer financing arrangements
Guarantor Obligations [Line Items]
Guarantee Obligations Maximum Potential Payment	17.3
Guarantee Liability Carrying Amount	13.0
Commercial customer financing arrangements | Maximum
Guarantor Obligations [Line Items]
Guarantee Obligation Term	6 years