Fair Value Measurements 2 (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Mar. 31, 2012
Carrying Value [Member]
Liabilities:
Total debt	$ 1,294	[1]	$ 1,301	[1]
Facilities abandonment reserve	33	[2]	42	[2]
Estimated Fair Value [Member]
Liabilities:
Total debt	1,437	[1]	1,408	[1]
Facilities abandonment reserve	$ 38	[2]	$ 48	[2]

[1] Estimated fair value of total debt is based on quoted prices for similar liabilities for which significant inputs are observable except for certain long-term lease obligations, for which fair value approximates carrying value (Level 2).

[2] Estimated fair value for the facilities abandonment reserve is determined using the Company’s incremental borrowing rate at September 30, 2012 and March 31, 2012. At September 30, 2012 and March 31, 2012, the facilities abandonment reserve included approximately $14 million and $16 million, respectively, in “Accrued expenses and other current liabilities” and approximately $19 million and $26 million, respectively, in “Other noncurrent liabilities” in the Company’s Condensed Consolidated Balance Sheets (Level 3).