Fair Value Measurements Investment Fair Value (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Investments [Abstract]
Investments	$ 14,869		$ 14,500
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	958		337
Investment Segment [Member]
Investments [Abstract]
Investments	14,393		13,961
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	958		337
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member]
Investments [Abstract]
Investments	14,393		13,961
Derivative contracts, at fair value (asset)	43	[1]	3	[1]
Assets, Fair Value Disclosure	14,436		13,964
Securities sold, not yet purchased, at fair value:
Derivative contracts at fair value (liability)	840	[2]	614	[2]
Financial and Nonfinancial Liabilities, Fair Value Disclosure	1,798		951
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	957		334
Trading Securities	14,104		13,659
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Basic Materials [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	89		0
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Communications [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	3,050		2,846
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Consumer, non-cyclical [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	2,413		2,308
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Consumer, cyclical [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	879		334
Trading Securities	384		436
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Diversified [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	22		23
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Energy sector [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	1,608		1,895
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Financial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	69		417
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Funds [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	78		0
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Industrial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	210		99
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Technology [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	6,259		5,635
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	120		129
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Consumer, cyclical [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	75		75
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Energy sector [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	12		19
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Financial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	8		7
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Utilities [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	25		28
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Financial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	169		173
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | Consumer, non-cyclical [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	958		337
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | Energy sector [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	1		3
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Investments [Abstract]
Investments	14,081		13,639
Derivative contracts, at fair value (asset)	0	[1]	0	[1]
Assets, Fair Value Disclosure	14,081		13,639
Securities sold, not yet purchased, at fair value:
Derivative contracts at fair value (liability)	0	[2]	0	[2]
Financial and Nonfinancial Liabilities, Fair Value Disclosure	927		334
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	927		334
Trading Securities	14,081		13,639
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Basic Materials [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	66		0
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Communications [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	3,050		2,846
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Consumer, non-cyclical [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	2,413		2,308
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Consumer, cyclical [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	879		334
Trading Securities	384		436
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Diversified [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	22		23
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Energy sector [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	1,608		1,895
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Financial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	69		417
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Funds [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	48		0
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Industrial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	210		79
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Technology [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	6,259		5,635
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Consumer, cyclical [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Energy sector [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Financial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Utilities [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Financial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | Consumer, non-cyclical [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	927		334
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | Energy sector [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Investments [Abstract]
Investments	237		247
Derivative contracts, at fair value (asset)	43	[1]	3	[1]
Assets, Fair Value Disclosure	280		250
Securities sold, not yet purchased, at fair value:
Derivative contracts at fair value (liability)	840	[2]	614	[2]
Financial and Nonfinancial Liabilities, Fair Value Disclosure	871		617
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	30		0
Trading Securities	23		20
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Basic Materials [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	23		0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Communications [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Consumer, non-cyclical [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Consumer, cyclical [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	0		0
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Diversified [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Energy sector [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Financial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Funds [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	30		0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Industrial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		20
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Technology [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	45		54
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Consumer, cyclical [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Energy sector [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	12		19
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Financial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	8		7
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Utilities [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	25		28
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Financial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	169		173
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | Consumer, non-cyclical [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	31		3
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | Energy sector [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	1		3
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Investments [Abstract]
Investments	75		75
Derivative contracts, at fair value (asset)	0	[1]	0	[1]
Assets, Fair Value Disclosure	75		75
Securities sold, not yet purchased, at fair value:
Derivative contracts at fair value (liability)	0	[2]	0	[2]
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	0		0
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Basic Materials [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Communications [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Consumer, non-cyclical [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Consumer, cyclical [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	0		0
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Diversified [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Energy sector [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Financial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Funds [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Industrial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Technology [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	75		75
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Consumer, cyclical [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	75		75
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Energy sector [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Financial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Utilities [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Financial [Member]
Securities sold, not yet purchased, at fair value:
Trading Securities	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | Consumer, non-cyclical [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	0		0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | Energy sector [Member]
Securities sold, not yet purchased, at fair value:
Securities sold, not yet purchased, at fair value	$ 0		$ 0

[1] Included in other assets in our condensed consolidated balance sheets.

[2] Included in accrued expenses and other liabilities in our condensed consolidated balance sheets.