Income Taxes (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Investments in foreign subsidiaries	$ 4,100
Effective tax rate	30.10%	26.50%	3.80%
Valuation allowances	1	4
Valuation allowances, beginning balance	7	1
Net Operating Loss Carryforwards	78.00%
Domestic deferred tax assets	240
Unrecognized tax benefits that would impact effective tax rate	102	123
Accured interest and penalties	17	35
Putnam and issues included in consolidated mmc tax returns	143	199	206	293
Unrecognized tax benefits minimum	0
Unrecognized tax benefits maximum	80
Putnam and Kroll [Member]
Putnam and issues included in consolidated mmc tax returns	14	75	80
State and Local Jurisdiction [Member]
Potential tax benefit from net operating loss carryforwards	93
Non US [Member]
Potential tax benefit from net operating loss carryforwards	$ 82