Derivative Financial Instruments and Hedging Activities (Details) (USD $) In Millions	Jun. 30, 2011
US dollar [Member]
Interest Rate Risk
Interest rate derivatives cashflow hedges, Notional Amount	$ 840
Interest rate derivatives cashflow hedges, Fair value	10
Pounds sterling [Member]
Interest Rate Risk
Interest rate derivatives cashflow hedges, Notional Amount	250
Interest rate derivatives cashflow hedges, Fair value	3
Euro [Member]
Interest Rate Risk
Interest rate derivatives cashflow hedges, Notional Amount	146
Interest rate derivatives cashflow hedges, Fair value	$ 0