Total costs accrued as of the balance sheet date for environmental loss contingencies.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Name:	us-gaap_AccrualForEnvironmentalLossContingencies
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Commitments and Contingencies (Environmental) (Details) (USD $)				3 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Superfund sites Superfund_Sites	Sep. 30, 2013 Homer City Pennsylvania [Member]
Site Contingency [Line Items]
Penalty in excess of $100,000				$ 100,000
Accrual for Environmental Loss Contingencies Disclosure [Abstract]
Accrual for Environmental Loss Contingencies	69,000,000	72,000,000
Accrual for site contingency			$ 5,000,000
Number of superfund sites			8