Fiduciary Assets And Liabilities (Details) (USD $)	9 Months Ended	12 Months Ended	9 Months Ended
	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2011 Risk and Insurance Services [Member]	Sep. 30, 2010 Risk and Insurance Services [Member]	Sep. 30, 2011 Consulting [Member]	Sep. 30, 2010 Consulting [Member]
Interest on fiduciary funds			$ 36,000,000	$ 33,000,000	$ 3,000,000	$ 3,000,000
Fixed income securities in fiduciary assets	102,000,000	283,000,000
Unrealized gains, net of tax	1,000,000	5,000,000
Net uncollected premiums and claims receivable and payable	$ 9,100,000,000	$ 9,100,000,000