Leasing Activities (Cross-Border Energy Lease Investments) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Leasing Activities [Abstract]
Scheduled lease payments to PHI, net of non-recourse debt	$ 2,120		$ 2,265
Less: Unearned and deferred income	(771)		(842)
Investment in finance leases held in trust	1,349	[1]	1,423	[1]
Less: Deferred income tax liabilities	(793)		(816)
Net investment in finance leases held in trust	$ 556		$ 607

[1] Excludes the credit ratings of collateral posted by the lessees in these transactions.