Leasing Activities (Cross-Border Energy Lease Investments) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Leasing Activities [Abstract]
Scheduled lease payments to PHI, net of non-recourse debt	$ 2,120	$ 2,120
Less: Unearned and deferred income	(758)	(771)
Investment in finance leases held in trust	1,362	1,349
Less: Deferred income tax liabilities	(797)	(793)
Net investment in finance leases held in trust	$ 565	$ 556