Consolidated Statements Of Income (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Income Statement [Abstract]
Revenue	$ 3,026	$ 2,928	$ 6,077	$ 5,812
Expense:
Compensation and benefits	1,776	1,728	3,572	3,449
Other operating expenses	732	735	1,460	1,426
Operating expenses	2,508	2,463	5,032	4,875
Operating Income	518	465	1,045	937
Interest income	6	5	12	12
Interest expense	(45)	(49)	(91)	(100)
Investment income (loss)	4	(6)	24	13
Income before income taxes	483	415	990	862
Income tax expense	144	129	297	257
Income from continuing operations	339	286	693	605
Discontinued operations, net of tax	(2)	3	(2)	15
Net income before non-controlling interest	337	289	691	620
Less: Net income attributable to non-controlling interests	8	7	15	13
Net income attributable to the Company	$ 329	$ 282	$ 676	$ 607
Basic net income per share
- Continuing operations	$ 0.61	$ 0.51	$ 1.24	$ 1.08
- Net income attributable to the Company	$ 0.60	$ 0.51	$ 1.24	$ 1.10
Diluted net income per share
- Continuing operations	$ 0.60	$ 0.50	$ 1.23	$ 1.06
- Net income attributable to the Company	$ 0.59	$ 0.50	$ 1.22	$ 1.09
Average number of shares outstanding
- Basic (in shares)	545	547	544	545
- Diluted (in shares)	553	555	552	554
Shares outstanding at June 30, (in shares)	544	541	544	541