Derivative Instruments and Hedging Activities (Details) - Mar. 31, 2012 - Derivatives designated as hedging instruments - Cash flow hedges - Interest Rate Swaps - 3 month LIBOR interest rate swap, cash flow hedge terminated March 2012 - USD ($) $ in Millions	Total
Interest Rate Swap Agreements
Debt issued	$ 400
Interest rate swap loss amortized as an increase to interest expense over the remaining term of the debt	23
Other, net
Interest Rate Swap Agreements
Ineffective portion of the cash flow hedges	$ 2