Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 288.9	$ 464.6	$ 551.5
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of fixed assets and intangible assets	157.4	147.7	150.9
Provision for uncollectible receivables	12.6	16.3	10.4
Amortization of restricted stock and other non-cash compensation	43.1	44.5	51.7
Net amortization of bond discounts (premiums) and deferred financing costs	8.6	1.8	(8.7)
Non-cash loss related to early extinguishment of debt	15.2	0	0
Deferred income tax provision	69.4	103.6	83.9
Gain on sale of an investment	0	(93.6)	(132.2)
Other	3.2	12.3	28.2
Changes in assets and liabilities, net of acquisitions and dispositions, providing cash
Accounts receivable	(157.1)	(44.7)	(219.2)
Expenditures billable to clients	(241.5)	(73.8)	(39.2)
Other current assets	(11.3)	3.5	(42.0)
Accounts payable	417.7	(120.4)	(62.9)
Accrued liabilities	(17.4)	(57.8)	3.9
Other non-current assets and liabilities	(4.1)	46.8	102.8
Net cash provided by operating activities	592.9	357.2	273.5
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(173.0)	(169.2)	(140.3)
Acquisitions, including deferred payments, net of cash acquired	(61.5)	(145.5)	(63.1)
Proceeds from the sale of an investment	0	94.8	133.5
Other investing activities	10.0	9.7	11.1
Net cash used in investing activities	(224.5)	(210.2)	(58.8)
CASH FLOWS FROM FINANCING ACTIVITIES:
Purchase of long-term debt	(602.4)	(401.5)	(38.9)
Proceeds from issuance of long-term debt	0	1,044.6	0
Repurchase of common stock	(481.8)	(350.5)	(400.8)
Common stock dividends	(126.0)	(103.4)	(111.1)
Exercise of stock options	47.4	10.8	12.0
Acquisition-related payments	(27.6)	(37.1)	(71.5)
Net increase in short term bank borrowings	5.4	12.6	42.5
Distributions to noncontrolling interests	(14.9)	(17.0)	(23.0)
Preferred stock dividends	(11.6)	(11.6)	(11.6)
Excess tax benefit on share-based compensation	0	15.0	8.4
Other financing activities	(0.8)	(30.6)	53.0
Net cash (used in) provided by financing activities	(1,212.3)	131.3	(541.0)
Effect of foreign exchange rate changes on cash and cash equivalents	(94.1)	(6.2)	(46.7)
Net (decrease) increase in cash and cash equivalents	(938.0)	272.1	(373.0)
Cash and cash equivalents at beginning of period	2,574.8	2,302.7	2,675.7
Cash and cash equivalents at end of period	$ 1,636.8	$ 2,574.8	$ 2,302.7