Dispositions (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2012
Saline [Member]
Dispositions [Line Items]
Pre-tax loss	$ 96
Contractual obligation	182
Long-term Purchase Commitment, Time Period	P6Y
Sandusky [Member]
Dispositions [Line Items]
Pre-tax loss	77
Long-term Purchase Commitment, Time Period	four and one-half
Contractual obligation	$ 15