Financial Instruments (Estimated Fair Value of Debt, Financing and Capital Lease Obligations) (Details) (Successor [Member], USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Mar. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current and long-term debt, financing and capital lease obligations, Carrying amount	$ 31,816	$ 32,277
Liabilities, Fair Value Disclosure, Nonrecurring	32,684	34,199
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Fair Value Disclosure, Nonrecurring	26,595	27,516
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Fair Value Disclosure, Nonrecurring	4,954	5,421
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Fair Value Disclosure, Nonrecurring	$ 1,135	$ 1,262