Fair Value Measurements - Assets Measured at Fair Value on Non-recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Property Subject to or Available for Operating Lease [Line Items]
Fair Value	$ 329	$ 252
Significant Unobservable Inputs (Level 3) [Member]
Property Subject to or Available for Operating Lease [Line Items]
Fair Value	4	5
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Property Subject to or Available for Operating Lease [Line Items]
Fair Value	148	150
Total Losses	(70)	(100)
Fair Value, Measurements, Nonrecurring [Member] | Equipment Under Operating Leases [Member] | Significant Unobservable Inputs (Level 3) [Member]
Property Subject to or Available for Operating Lease [Line Items]
Fair Value	79	132
Total Losses	(39)	(95)
Fair Value, Measurements, Nonrecurring [Member] | Assets Held-for-sale or re-lease [Member] | Significant Unobservable Inputs (Level 3) [Member]
Property Subject to or Available for Operating Lease [Line Items]
Fair Value	69	18
Total Losses	$ (31)	$ (5)