Employee Benefits (Tables)

9 Months Ended

Sep. 30, 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 September 30,
	U.K.						U.S.						Other
	2014			2013			2014			2013			2014			2013
Service cost	$	—		$	—		$	—		$	—		$	—		$	5
Interest cost	58			52			32			28			12			11
Expected return on plan assets	(82		)	(74		)	(39		)	(34		)	(15		)	(15		)
Amortization of net actuarial loss	13			12			11			13			2			6
Total net periodic (benefit) cost	$	(11	)	$	(10	)	$	4		$	7		$	(1	)	$	7

	Nine months ended September 30,
	U.K.						U.S.						Other
	2014			2013			2014			2013			2014			2013
Service cost	$	—		$	—		$	—		$	—		$	—		$	14
Interest cost	174			156			96			84			36			33
Expected return on plan assets	(247		)	(223		)	(117		)	(103		)	(45		)	(44		)
Amortization of net actuarial loss	40			36			32			39			6			19
Net periodic (benefit) cost	(33		)	(31		)	11			20			(3		)	22
Curtailment loss (gain) and other	—			—			1			—			(3		)	—
Total net periodic (benefit) cost	$	(33	)	$	(31	)	$	12		$	20		$	(6	)	$	22