Employee Benefits (Tables)

3 Months Ended

Mar. 31, 2014

Compensation and Retirement Disclosure [Abstract]

Components of net periodic benefit cost for the pension plans

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

	Three months ended March 31,
	U.K.						U.S.						Other
	2014			2013			2014			2013			2014			2013
Service cost	$	—		$	—		$	—		$	—		$	—		$	5
Interest cost	58			53			32			28			12			11
Expected return on plan assets	(82		)	(75		)	(39		)	(34		)	(15		)	(15		)
Amortization of net actuarial loss	13			12			10			13			2			6
Net periodic (benefit) cost	(11		)	(10		)	3			7			(1		)	7
Curtailment loss (gain) and other	—			—			1			—			(3		)	—
Total net periodic benefit cost	$	(11	)	$	(10	)	$	4		$	7		$	(4	)	$	7