Long-Term Incentive Plans (Number Of Options Granted) (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2010	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted	1,100,000	1,100,000
Proxy Officers [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted		600,000
Other Senior Officers [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted
Senior Officers [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted		600,000
Other [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted		500,000