XML 24 R89.htm IDEA: XBRL DOCUMENT v2.4.0.6
Retirement Benefits (Schedule of Health Care Cost Trend Rates) (Detail)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Compensation And Retirement Disclosure [Abstract]    
Health care cost trend rate assumed for next year 7.00% 7.50%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) 4.50% 4.50%
Year that the rate reaches the ultimate trend rate 2018 2018