Asset Acquisitions, Dispositions and Other Transactions (Details 2) (USD $) In Millions, unless otherwise specified	6 Months Ended	1 Months Ended
Jun. 30, 2011	Mar. 31, 2011 7.0% senior notes due 2013	Mar. 31, 2011 6.75% senior notes due 2012
Debt instrument
Face amount of notes redeemed		$ 1,000	$ 368
Debt instrument interest rate stated percentage (as a percent)		7.00%	6.75%
Charges on debt extinguishment	$ 163

Decrease for amounts repaid on the debt instrument for the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph f
-Article 4

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Interest rate stated in the contractual debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount represents the difference between the fair value of the payments made and the carrying amount of the debt at the time of its extinguishment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 26
-Paragraph 20, 21

+ Details

Name:	us-gaap_GainsLossesOnExtinguishmentOfDebt
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration