Financing Receivables (Narrative) (Detail) (USD $) In Millions, unless otherwise specified	0 Months Ended	6 Months Ended
	Dec. 13, 2011	Jun. 30, 2012 Plant
Cash payment of lease	$ 7.5
Claim payable	110
Write off of gross lease investment		264
Number of plants		2
Energy Holdings [Member]
Lease investment with non-investment grade counterparties, gross		553
Lease investment with non-investment grade counterparties, net of deferred taxes		$ 57