Other Non-Operating Income - Additional Information (Detail) (Bayonne Energy Complex, USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2014
Schedule of Equity Method Investments [Line Items]
Joint venture ownership interest percentage	50.00%
Level 3 [Member]
Schedule of Equity Method Investments [Line Items]
Charge to reduce to fair value	$ 84
Charge to reduce to fair value, after income taxes	$ 52

The aggregate amount of other expense amounts, the components of which are not separately disclosed on the income statement, resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating expense recognized during the period. Such amounts may include: (a) unusual costs, (b) loss on foreign exchange transactions, (c) losses on securities (net of profits), and (d) miscellaneous other expense items.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 9

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.9)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Name:	us-gaap_OtherNonoperatingExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration