Quarterly Consolidated Financial Data (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended	3 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2013 Utility [Member]	Dec. 31, 2012 Utility [Member]	Sep. 30, 2012 Utility [Member]	Jun. 30, 2012 Utility [Member]	Mar. 31, 2012 Utility [Member]
Loss accrued				$ 110			$ 80
Insurance recoveries for cost incurred related to third-party claims				25	50	99	25	11
Disallowed capital expenditures	$ 196	$ 353	$ 0	$ 196	$ 353

The amount of indirect disallowance of costs of a recently completed plant. When it becomes probable that part of the cost of a recently completed plant will be disallowed for rate-making purposes and a reasonable estimate of the amount of the disallowance can be made, the estimated amount of the probable disallowance is deducted from the reported cost of the plant and recognized as a loss. If part of the cost is explicitly, but indirectly, disallowed (for example, by an explicit disallowance of return on investment on a portion of the plant), an equivalent amount of cost is deducted from the reported cost of the plant and recognized as a loss.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 980

-SubTopic 360

-Section 35

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6500292&loc=d3e45799-110387

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 980

-SubTopic 360

-Section 35

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=6500292&loc=d3e45819-110387

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration