Reorganization (Components Of Long-Term Debt) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
Liabilities Subject to Compromise, Debt and Accrued Interest	$ 1,198	$ 2,482
Secured Variable And Fixed Rate Indebtedness Due Through 2023 [Member]
Debt Instrument [Line Items]
Liabilities Subject to Compromise, Debt and Accrued Interest	172	1,456
Effective interest rate percentage - minimum	1.00%
Effective interest rate percentage - maximum	13.00%
Debt Instrument, Maturity Date Range, End	2023
6.00% - 8.50% Special Facility Revenue Bonds Due Through 2036 [Member]
Debt Instrument [Line Items]
Liabilities Subject to Compromise, Debt and Accrued Interest	186	186
Debt Instrument, Maturity Date Range, End	2036
Percentage of debt instrument interest rate - minimum	6.00%
Percentage of debt instrument interest rate - maximum	8.50%
6.25 Percent Senior Convertible Notes
Debt Instrument [Line Items]
Liabilities Subject to Compromise, Debt and Accrued Interest	460	460
Percentage of debt instrument, interest rate	6.25%
6.25% Senior Convertible Notes Due 2014 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date Range, End	2014
Percentage of debt instrument, interest rate	6.25%	6.25%
9.00% - 10.20% Debentures Due Through 2021 [Member]
Debt Instrument [Line Items]
Liabilities Subject to Compromise, Debt and Accrued Interest	214	214
Debt Instrument, Maturity Date Range, End	2021
Percentage of debt instrument interest rate - minimum	9.00%
Percentage of debt instrument interest rate - maximum	10.20%
7.88% - 10.55% Notes Due Through 2039 [Member]
Debt Instrument [Line Items]
Liabilities Subject to Compromise, Debt and Accrued Interest	$ 166	$ 166
Debt Instrument, Maturity Date Range, End	2039
Percentage of debt instrument interest rate - minimum	7.88%
Percentage of debt instrument interest rate - maximum	10.55%

When presenting a range of interest rates, the highest effective rate for funds borrowed under the debt agreement as of the balance sheet date.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

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When presenting a range of interest rates, the lowest effective rate for funds borrowed under the debt agreement as of the balance sheet date.

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Interest rate stated in the contractual debt agreement.

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When presenting a range of interest rates, the highest stated (contractual) rate for funds borrowed under the debt agreement as of the balance sheet date.

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When presenting a range of interest rates, the lowest stated (contractual) rate for funds borrowed under the debt agreement as of the balance sheet date.

+ 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

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(2))

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- Definition

When presenting a range of maturity dates, the latest date when the outstanding debt instruments are required to be repaid. May be presented in a variety of ways (for example: year only, month and year, day, month and year, and number of years).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(2))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

The amount of debt and related accrued interest included in liabilities subject to compromise.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 852

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6918054&loc=d3e56015-112765

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

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 90-7

-Paragraph 26

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 852

-SubTopic 10

-Section 55

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6585303&loc=d3e56145-112766

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-Name Accounting Standards Codification

-Topic 852

-SubTopic 10

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6916575&loc=d3e55717-112764

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