Risk Management Activities and Fair Value Measurements - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Jun. 30, 2011
Disclosure Risk Management Activities and Fair Value Measurements Additional Information [Abstract]
Derivative, Net Liability Position, Aggregate Fair Value	$ 377
Long-Term Debt Fair Value Disclosure	$ 21,950	$ 23,418

The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain or loss on that instrument.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 44D

-Subparagraph b

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