Restructuring Costs (Tables)

12 Months Ended

Dec. 31, 2014

Restructuring Cost and Reserve [Line Items]

Restructuring and Related Costs [Table Text Block]

	Twelve months ended December 31, 2014
	Willis North America		Willis International		Willis GB		Willis CWR		Corporate		Total
	(millions)
Termination benefits	$	3	$	3	$	9	$	1	$	—	$	16
Professional services and other	—		2		1		—		17		20
Total	$	3	$	5	$	10	$	1	$	17	$	36

Schedule of Restructuring Reserve by Type of Cost [Table Text Block]

	Termination Benefits			Professional Services and other			Total
	(millions)
Balance at January 1, 2014	$	—		$	—		$	—
Charges incurred	16			20			36
Cash payments	(11		)	(14		)	(25		)
Balance at December 31, 2014	$	5		$	6		$	11