Nature Of Operations (Details) (USD $) In Millions	0 Months Ended		6 Months Ended	1 Months Ended	3 Months Ended	6 Months Ended
Aug. 03, 2010 Kroll Divestiture [Member]	Jun. 30, 2011 Kroll Divestiture [Member]	Jun. 30, 2011 Acquisition Haake Companies Inc [Member]	Jun. 30, 2011 Acquisition HSBC Insurance Brokers Ltd [Member]	Jun. 30, 2011 Acquisition Bostonian Group [Member]	Jun. 30, 2011 Acquisition Trion [Member]	Jun. 30, 2011 Acquisition SBS [Member]	Jun. 30, 2011 Acquisition RJF [Member]	Jun. 30, 2011 Acquisition Hampton Roads [Member]	Jun. 30, 2011 Acquisition Evaluation Associates LLC [Member]	Jul. 31, 2010 Acquisition Innovative Process Administration [Member]	Aug. 31, 2010 Acquisition ORC Worldwide [Member]	Mar. 31, 2011 Acquisition Hammond Associates [Member]	Jun. 30, 2011 Acquisition Thomas Rutherfoord Inc [Member]
Cash provided from sale of Kroll	$ 1,130
MMC sale date of Kroll to Altegrity		Aug. 03, 2010
Acquisition date			2010-03-31	2010-04-01	2010-04-01	2010-12-31	2010-12-31	2011-01-31	2011-02-28	2011-06-30	2010-07-31	2010-08-31	2011-03-31	2010-03-31

Month, date and year in which the acquirer obtains control of the acquiree.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6909708&loc=d3e848-128460

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6909870&loc=d3e1392-128463

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Paragraph 3
-Subparagraph c
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6909708&loc=d3e845-128460

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Paragraph 10, 11
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Paragraph 68
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Acquisition Date
-URI http://asc.fasb.org/extlink&oid=6919109

+ Details