(dollars in millions) | 2013 | 2012 | 2011 | |||||||||
Impact on net assets of indemnity settlement with BP Exploration and Production, Inc. | $ | – | $ | – | $ | (82.5 | ) | |||||
Tax benefit of stock compensation plan transactions | $ | 9.5 | $ | 11.5 | $ | 4.9 | ||||||
Change in fair value of derivatives accounted for as cash flow hedges, net of tax | $ | 13.8 | $ | 10.1 | $ | (5.2 | ) | |||||
Actuarial gain (loss), net, related to defined benefit pension and postretirement benefit plans | $ | 13.6 | $ | (33.3 | ) | $ | (7.7 | ) | ||||