Income Taxes (Narrative) (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Abstract]
Investments in foreign subsidiaries			$ 5,200,000,000
Effective tax rate			30.10%	29.00%	30.10%
Valuation allowances		(1,000,000)	10,000,000	23,000,000
Valuation allowances, beginning balance	16,000,000		(3,000,000)
Net Operating Loss Carryforwards			66.00%
Unrecognized tax benefits that would impact effective tax rate			71,000,000	96,000,000	102,000,000
Accrued interest and penalties			10,000,000	13,000,000	17,000,000
Unrecognized tax benefits minimum			0
Unrecognized tax benefits maximum			21,000,000
Tax Credit Carryforward [Line Items]
Putnam and issues included in consolidated mmc tax returns			128,000,000	117,000,000	143,000,000	199,000,000
State and Local Jurisdiction [Member]
Tax Credit Carryforward [Line Items]
Unrecognized Tax Benefits Resulting in Net Operating Loss Carryforward			60,000,000
Foreign Tax Authority [Member]
Tax Credit Carryforward [Line Items]
Unrecognized Tax Benefits Resulting in Net Operating Loss Carryforward			90,000,000
Internal Revenue Service (IRS) [Member]
Tax Credit Carryforward [Line Items]
Domestic deferred tax assets			195,000,000
Putnam and Kroll [Member]
Tax Credit Carryforward [Line Items]
Putnam and issues included in consolidated mmc tax returns			$ 2,000,000	$ 6,000,000	$ 14,000,000