Retirement Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2017

General Discussion of Pension and Other Postretirement Benefits [Abstract]

Schedule of defined benefit plans

The components of net periodic benefit cost in respect of these defined benefit plans are as follows:

	For the three months ended March 31,
$ in millions	2017		2016
Service cost	1.2		1.4
Interest cost	4.1		4.4
Expected return on plan assets	(5.4	)	(5.7	)
Amortization of net actuarial (gain)/loss	0.6		0.5
Net periodic benefit cost/(benefit)	0.5		0.6