Other Assets and Investments (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Long Lived Assets Held-for-sale [Line Items]
Investment Owned, Balance, Shares	3,421,306	3,421,306
Investment Owned, at Fair Value	$ 41	$ 36
Available-for-sale Securities, Gross Unrealized Gains	24	19
Available For Sale Securities Gross Unrealized Holding Gains After Tax	26	21
Proceeds from Dividends Received	168	126	129
Equity Method Investment, Dividends or Distributions	8	4	3
Return of investment in The Reserve Primary Fund	$ 0	$ 26	$ 47