Weighted Average Common Shares (Narrative) (Detail) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive awards excluded from computations of diluted earnings per share		3.1		2.7
Weighted average number of shares issued, maximum	0.1	0.1	0.1	0.1