Employee Benefits

The following table provides the components of the net periodic benefit cost for Aon’s U.S. pension plans, along with its most significant international pension plans, which are located in the U.K., the Netherlands and Canada (in millions):



	Three months ended September 30,
	U.K. and Non-U.S.						U.S.
	2013			2012			2013			2012
Service cost	$	5		$	4		$	—		$	—
Interest cost	63			66			28			29
Expected return on plan assets	(89		)	(80		)	(34		)	(31		)
Amortization of net actuarial loss	18			15			13			10
Net periodic (benefit) cost	$	(3	)	$	5		$	7		$	8



	Nine months ended September 30,
	U.K. and Non-U.S.						U.S.
	2013			2012			2013			2012
Service cost	$	14		$	12		$	—		$	—
Interest cost	189			198			84			89
Expected return on plan assets	(267		)	(241		)	(103		)	(95		)
Amortization of net actuarial loss	55			44			39			32
Net periodic (benefit) cost	$	(9	)	$	13		$	20		$	26

Based on current assumptions, in 2013, Aon plans to contribute $167 million and $381 million to its U.S. and most significant international defined benefit pension plans, respectively. During the three months ended September 30, 2013, contributions of $54 million were made to the Company's U.S. pension plans and $59 million were made to its most significant international pension plans. During the nine months ended September 30, 2013, contributions of $122 million were made to the Company’s U.S. pension plans and $290 million were made to its most significant international pension plans.