Leasing Activities (Cross-Border Energy Lease Investments) (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Scheduled lease payments to PHI, net of non-recourse debt	$ 1,852	$ 2,120
Less: Unearned and deferred income	(626)	(771)
Investment in finance leases held in trust	1,226	1,349
Less: Deferred income tax liabilities	(738)	(793)
Net investment in finance leases held in trust	$ 488	$ 556