Indebtedness (Schedule Of Maturities Of Long-Term Debt) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	$ 1,181
Long-term Debt, Maturities, Repayments of Principal in Year Two	1,482
Long-term Debt, Maturities, Repayments of Principal in Year Three	773
Long-term Debt, Maturities, Repayments of Principal in Year Four	1,828
Long-term Debt, Maturities, Repayments of Principal in Year Five	545
Principal Not Subject To Compromise [Member]
Debt Instrument [Line Items]
Payments Not Made Due to Chapter 11 Proceedings	451
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	1,004
Long-term Debt, Maturities, Repayments of Principal in Year Two	870
Long-term Debt, Maturities, Repayments of Principal in Year Three	768
Long-term Debt, Maturities, Repayments of Principal in Year Four	1,762
Long-term Debt, Maturities, Repayments of Principal in Year Five	503
Principal Subject To Compromise [Member]
Debt Instrument [Line Items]
Payments Not Made Due to Chapter 11 Proceedings	148
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	177
Long-term Debt, Maturities, Repayments of Principal in Year Two	612
Long-term Debt, Maturities, Repayments of Principal in Year Three	5
Long-term Debt, Maturities, Repayments of Principal in Year Four	66
Long-term Debt, Maturities, Repayments of Principal in Year Five	$ 42