Fair Value Measurements (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Financial instruments owned:
Mutual funds	$ 137	[1]	$ 134	[1]
Money market funds	284	[2]	226	[2]
Interest rate swap derivatives	6	[3]	7	[3]
Total assets measured at fair value	427		367
Fiduciary Assets:
State and local obligations (including non-U.S. locales)	5		13
Other sovereign government obligations and supranational agencies			47
Corporate and other debt	0		2
Money market funds	179		186
Total fiduciary assets measured at fair value	184		248
Liabilities:
Contingent consideration liability	77	[4]	110	[4]
Senior Notes due 2014	256	[5]	257	[5]
Total liabilities measured at fair value	333		367
Identical Assets (Level 1) [Member]
Financial instruments owned:
Mutual funds	137	[1]	134	[1]
Money market funds	284	[2]	226	[2]
Interest rate swap derivatives	0		0
Total assets measured at fair value	421		360
Fiduciary Assets:
State and local obligations (including non-U.S. locales)	0		0
Other sovereign government obligations and supranational agencies	0		0
Corporate and other debt	0		0
Money market funds	179		186
Total fiduciary assets measured at fair value	179		186
Liabilities:
Contingent consideration liability	0		0
Senior Notes due 2014	0		0
Total liabilities measured at fair value	0		0
Observable Inputs (Level 2) [Member]
Financial instruments owned:
Mutual funds	0		0
Money market funds	0		0
Interest rate swap derivatives	6	[3]	7	[3]
Total assets measured at fair value	6		7
Fiduciary Assets:
State and local obligations (including non-U.S. locales)	5		13
Other sovereign government obligations and supranational agencies			47
Corporate and other debt	0		2
Money market funds	0		0
Total fiduciary assets measured at fair value	5		62
Liabilities:
Contingent consideration liability	0		0
Senior Notes due 2014	256	[5]	257	[5]
Total liabilities measured at fair value	256		257
Unobservable Inputs (Level 3) [Member]
Financial instruments owned:
Mutual funds	0		0
Money market funds	0		0
Interest rate swap derivatives	0		0
Total assets measured at fair value	0		0
Fiduciary Assets:
State and local obligations (including non-U.S. locales)	0		0
Other sovereign government obligations and supranational agencies	0		0
Corporate and other debt	0		0
Money market funds	0		0
Total fiduciary assets measured at fair value	0		0
Liabilities:
Contingent consideration liability	77	[4]	110	[4]
Senior Notes due 2014	0		0
Total liabilities measured at fair value	$ 77		$ 110

[1] Included in other assets in the consolidated balance she

[2] Included in cash and cash equivalents in the consolidated balance sheet

[3] Included in other receivables in the consolidated balance she

[4] Included in accounts payable and accrued liabilities and other liabilities in the consolidated balance she

[5] Included in long term debt in the consolidated balance she