Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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+ Details

Goodwill And Other Intangibles (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Goodwill	$ 6,675	$ 6,557	$ 6,562	$ 6,420
Aggregate amortization expense	17	16
Risk and Insurance Services [Member]
Segment Reporting Information [Line Items]
Goodwill	4,600
Consulting [Member]
Segment Reporting Information [Line Items]
Goodwill	$ 2,100