Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 464.6	$ 551.5	$ 281.2
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of fixed assets and intangible assets	147.7	150.9	148.4
Provision for uncollectible receivables	16.3	10.4	10.7
Amortization of restricted stock and other non-cash compensation	44.5	51.7	50.0
Net amortization of bond discounts (premiums) and deferred financing costs	1.8	(8.7)	(4.4)
Deferred income tax provision	103.6	83.9	56.0
Gain on sale of an investment	(93.6)	(132.2)	0
Other	12.3	28.2	25.0
Changes in assets and liabilities, net of acquisitions and dispositions, providing (using) cash:
Accounts receivable	(44.7)	(219.2)	(547.6)
Expenditures billable to clients	(73.8)	(39.2)	(122.8)
Other current assets	3.5	(42.0)	(0.2)
Accounts payable	(120.4)	(62.9)	867.4
Accrued liabilities	(57.8)	3.9	66.4
Other non-current assets and liabilities	(46.8)	(102.8)	(12.8)
Net cash provided by operating activities	357.2	273.5	817.3
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(169.2)	(140.3)	(96.3)
Acquisitions, including deferred payments, net of cash acquired	(145.5)	(63.1)	(61.9)
Proceeds from the sale of an investment	94.8	133.5	0
Other investing activities	9.7	11.1	49.7
Net cash used in investing activities	(210.2)	(58.8)	(108.5)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of long-term debt	1,044.6	0	0
Purchase of long-term debt	(401.5)	(38.9)	(217.3)
Repurchase of common stock	(350.5)	(400.8)	0
Common stock dividends	(103.4)	(111.1)	0
Repurchase of preferred stock	0	0	(265.9)
Acquisition-related payments	(37.1)	(71.5)	(29.5)
Distributions to noncontrolling interests	(17.0)	(23.0)	(21.5)
Preferred stock dividends	(11.6)	(11.6)	(19.6)
Net increase in short term bank borrowings	12.6	42.5	17.4
Other financing activities	(4.8)	73.4	(11.3)
Net cash provided by (used in) financing activities	131.3	(541.0)	(547.7)
Effect of foreign exchange rate changes on cash and cash equivalents	(6.2)	(46.7)	19.4
Net increase (decrease) in cash and cash equivalents	272.1	(373.0)	180.5
Cash and cash equivalents at beginning of period	2,302.7	2,675.7	2,495.2
Cash and cash equivalents at end of period	$ 2,574.8	$ 2,302.7	$ 2,675.7