Segments - Business Segment Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Segment Information [Line Items]
Revenues	$ 1,376	$ 1,334
Depreciation and amortization	126	129
Restructuring charges	35	37
Stock-based compensation expense	10	8
Other items	7	2
Operating income/(loss)	171	157
Business segment income/(loss)	349	333
Total assets	14,416		14,585
Buy [Member]
Segment Information [Line Items]
Revenues	825	799
Depreciation and amortization	51	53
Restructuring charges	12	31
Stock-based compensation expense	3	2
Other items	5
Operating income/(loss)	53	35
Business segment income/(loss)	124	121
Total assets	6,705		6,885
Watch [Member]
Segment Information [Line Items]
Revenues	494	474
Depreciation and amortization	68	68
Restructuring charges	7	5
Stock-based compensation expense	2	2
Operating income/(loss)	122	111
Business segment income/(loss)	199	186
Total assets	6,696		6,706
Expositions [Member]
Segment Information [Line Items]
Revenues	57	61
Depreciation and amortization	6	6
Operating income/(loss)	26	30
Business segment income/(loss)	32	36
Total assets	752		758
Corporate [Member]
Segment Information [Line Items]
Depreciation and amortization	1	2
Restructuring charges	16	1
Stock-based compensation expense	5	4
Other items	2	2
Operating income/(loss)	(30)	(19)
Business segment income/(loss)	(6)	(10)
Total assets	$ 263		$ 236