Asset-Backed Financing (Assets And Liabilities Of Variable Interest Entities) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jul. 01, 2012
Financing Receivable [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	$ 2,426,061	$ 2,337,993	$ 2,090,778
Financing Receivable [Member] | Asset-backed Securities [Member] | SPEs [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	2,223,167	2,143,708	2,082,375
Financing Receivable [Member] | Asset-backed U.S. Commercial Paper Conduit Facility [Member] | SPEs [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	0	0	8,403
Financing Receivable [Member] | Asset-Backed Canadian Commercial Paper Conduit Facility [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	202,894	194,285	0
Allowance for Credit Loss [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Associated Liabilities, Carrying Amount	(47,274)	(45,571)	(41,949)
Allowance for Credit Loss [Member] | Asset-backed Securities [Member] | SPEs [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Associated Liabilities, Carrying Amount	(43,727)	(42,139)	(41,781)
Allowance for Credit Loss [Member] | Asset-backed U.S. Commercial Paper Conduit Facility [Member] | SPEs [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Associated Liabilities, Carrying Amount	0	0	(168)
Allowance for Credit Loss [Member] | Asset-Backed Canadian Commercial Paper Conduit Facility [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Associated Liabilities, Carrying Amount	(3,547)	(3,432)	0
Restricted Cash [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	212,004	188,008	188,564
Restricted Cash [Member] | Asset-backed Securities [Member] | SPEs [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	198,893	176,290	187,782
Restricted Cash [Member] | Asset-backed U.S. Commercial Paper Conduit Facility [Member] | SPEs [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	0	0	782
Restricted Cash [Member] | Asset-Backed Canadian Commercial Paper Conduit Facility [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	13,111	11,718	0
Other Assets [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	4,365	5,543	4,401
Other Assets [Member] | Asset-backed Securities [Member] | SPEs [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	4,082	4,869	4,243
Other Assets [Member] | Asset-backed U.S. Commercial Paper Conduit Facility [Member] | SPEs [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	174	419	158
Other Assets [Member] | Asset-Backed Canadian Commercial Paper Conduit Facility [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	109	255	0
Assets, Total [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	2,595,156	2,485,973	2,241,794
Assets, Total [Member] | Asset-backed Securities [Member] | SPEs [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	2,382,415	2,282,728	2,232,619
Assets, Total [Member] | Asset-backed U.S. Commercial Paper Conduit Facility [Member] | SPEs [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	174	419	9,175
Assets, Total [Member] | Asset-Backed Canadian Commercial Paper Conduit Facility [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	212,567	202,826	0
Asset-backed debt [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	1,848,988	1,623,434	1,339,232
Asset-backed debt [Member] | Asset-backed Securities [Member] | SPEs [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	1,673,759	1,447,776	1,339,232
Asset-backed debt [Member] | Asset-backed U.S. Commercial Paper Conduit Facility [Member] | SPEs [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	0	0	0
Asset-backed debt [Member] | Asset-Backed Canadian Commercial Paper Conduit Facility [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Transfers Accounted for as Secured Borrowings, Assets, Carrying Amount	$ 175,229	$ 175,658	$ 0