Emergence From Chapter 11 (Components of Long-Term Debt) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Debt Instrument [Line Items]
Long-term debt	$ 1,198
Secured variable and fixed rate indebtedness due through 2023 (effective rates from 1.00% - 13.00% at December 31, 2012)
Debt Instrument [Line Items]
Effective interest rate percentage - minimum	1.00%
Effective interest rate percentage - maximum	13.00%
Debt instrument maturity date	Dec. 31, 2023
6.00%—8.50% special facility revenue bonds due through 2036
Debt Instrument [Line Items]
Percentage of debt instrument interest rate - minimum	6.00%
Percentage of debt instrument interest rate - maximum	8.50%
Debt instrument maturity date	Dec. 31, 2036
6.25% senior convertible notes due 2014
Debt Instrument [Line Items]
Stated interest rate percentage	6.25%
Debt instrument maturity date	Dec. 31, 2014
9.0%—10.20% debentures due through 2021
Debt Instrument [Line Items]
Percentage of debt instrument interest rate - minimum	9.00%
Percentage of debt instrument interest rate - maximum	10.20%
Debt instrument maturity date	Dec. 31, 2021
7.88%—10.55% notes due through 2039
Debt Instrument [Line Items]
Percentage of debt instrument interest rate - minimum	7.88%
Percentage of debt instrument interest rate - maximum	10.55%
Debt instrument maturity date	Dec. 31, 2039
Classified As Subject to Compromise [Member] | Secured variable and fixed rate indebtedness due through 2023 (effective rates from 1.00% - 13.00% at December 31, 2012)
Debt Instrument [Line Items]
Long-term debt	172
Classified As Subject to Compromise [Member] | 6.00%—8.50% special facility revenue bonds due through 2036
Debt Instrument [Line Items]
Long-term debt	186
Classified As Subject to Compromise [Member] | 6.25% senior convertible notes due 2014
Debt Instrument [Line Items]
Long-term debt	460
Classified As Subject to Compromise [Member] | 9.0%—10.20% debentures due through 2021
Debt Instrument [Line Items]
Long-term debt	214
Classified As Subject to Compromise [Member] | 7.88%—10.55% notes due through 2039
Debt Instrument [Line Items]
Long-term debt	166
AA [Member]
Debt Instrument [Line Items]
Long-term debt	358
AA [Member] | Secured variable and fixed rate indebtedness due through 2023 (effective rates from 1.00% - 13.00% at December 31, 2012)
Debt Instrument [Line Items]
Effective interest rate percentage - minimum	1.00%
Effective interest rate percentage - maximum	13.00%
Debt instrument maturity date	Dec. 31, 2023
AA [Member] | 6.00%—8.50% special facility revenue bonds due through 2036
Debt Instrument [Line Items]
Percentage of debt instrument interest rate - minimum	6.00%
Percentage of debt instrument interest rate - maximum	8.50%
Debt instrument maturity date	Dec. 31, 2036
AA [Member] | Classified As Subject to Compromise [Member] | Secured variable and fixed rate indebtedness due through 2023 (effective rates from 1.00% - 13.00% at December 31, 2012)
Debt Instrument [Line Items]
Long-term debt	172
AA [Member] | Classified As Subject to Compromise [Member] | 6.00%—8.50% special facility revenue bonds due through 2036
Debt Instrument [Line Items]
Long-term debt	$ 186