Segment Information Schedule of fiduciary investment income by business segment (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Fiduciary investment income	$ 7	$ 8	$ 6	$ 7	$ 7	$ 11	$ 8	$ 12	$ 28	$ 38	$ 52
Risk Solutions [Member]
Segment Reporting Information [Line Items]
Fiduciary investment income									28	38	52
HR Solutions [Member]
Segment Reporting Information [Line Items]
Fiduciary investment income									$ 0	$ 0	$ 0