Fair Value Measurements Investment Fair Value (Details) - USD ($) $ in Millions		Jun. 30, 2015	Dec. 31, 2014
Investments [Abstract]
Investments		$ 14,466	$ 14,500
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		977	337
Investment Segment [Member]
Investments [Abstract]
Investments		13,952	13,961
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		977	337
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member]
Investments [Abstract]
Investments		13,952	13,961
Derivative contracts, at fair value (asset)	[1]	144	3
Assets, Fair Value Disclosure		14,096	13,964
Marketable Securities, Equity Securities [Abstract]
Derivative contracts at fair value (liability)	[2]	641	614
Mortgage-backed securities: [Abstract]
Financial and Nonfinancial Liabilities, Fair Value Disclosure		1,618	951
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		974	334
Trading Securities		13,692	13,659
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Basic Materials [Member]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		13	0
Trading Securities		95	0
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Communications [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		2,698	2,846
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Consumer, non-cyclical [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		2,573	2,308
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Consumer, cyclical [Member]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		908	334
Trading Securities		295	436
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Diversified [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		24	23
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Energy sector [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		1,076	1,895
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Financial [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		213	417
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Funds [Member]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		53	0
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Industrial [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		233	99
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Technology [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		6,485	5,635
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		94	129
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Consumer, cyclical [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		62	75
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Energy sector [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		3	19
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Financial [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		5	7
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Utilities [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		24	28
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Financial [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		166	173
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | Consumer, non-cyclical [Member]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		977	337
Investment Segment [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | Funds [Member]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		3	3
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Investments [Abstract]
Investments		13,552	13,639
Derivative contracts, at fair value (asset)	[1]	0	0
Assets, Fair Value Disclosure		13,552	13,639
Marketable Securities, Equity Securities [Abstract]
Derivative contracts at fair value (liability)	[2]	0	0
Mortgage-backed securities: [Abstract]
Financial and Nonfinancial Liabilities, Fair Value Disclosure		948	334
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		948	334
Trading Securities		13,552	13,639
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Basic Materials [Member]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		0	0
Trading Securities		65	0
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Communications [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		2,698	2,846
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Consumer, non-cyclical [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		2,573	2,308
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Consumer, cyclical [Member]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		908	334
Trading Securities		295	436
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Diversified [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		24	23
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Energy sector [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		1,050	1,895
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Financial [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		135	417
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Funds [Member]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		40	0
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Industrial [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		227	79
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Technology [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		6,485	5,635
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Marketable Securities, Equity Securities [Abstract]
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]
Marketable Securities, Equity Securities [Abstract]
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]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		0	0
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Financial [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		0	0
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Utilities [Member]
Marketable Securities, Equity Securities [Abstract]
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]
Marketable Securities, Equity Securities [Abstract]
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]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		948	334
Investment Segment [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | Funds [Member]
Marketable Securities, Equity Securities [Abstract]
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		338	247
Derivative contracts, at fair value (asset)	[1]	144	3
Assets, Fair Value Disclosure		482	250
Marketable Securities, Equity Securities [Abstract]
Derivative contracts at fair value (liability)	[2]	641	614
Mortgage-backed securities: [Abstract]
Financial and Nonfinancial Liabilities, Fair Value Disclosure		670	617
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		26	0
Trading Securities		140	20
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Basic Materials [Member]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		13	0
Trading Securities		30	0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Communications [Member]
Marketable Securities, Equity Securities [Abstract]
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]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		0	0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Consumer, cyclical [Member]
Marketable Securities, Equity Securities [Abstract]
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]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		0	0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Energy sector [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		26	0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Financial [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		78	0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Funds [Member]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		13	0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Industrial [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		6	20
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Technology [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		0	0
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		32	54
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Consumer, cyclical [Member]
Marketable Securities, Equity Securities [Abstract]
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]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		3	19
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Financial [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		5	7
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Utilities [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		24	28
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Financial [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		166	173
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | Consumer, non-cyclical [Member]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		29	3
Investment Segment [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member] | Funds [Member]
Marketable Securities, Equity Securities [Abstract]
Securities sold, not yet purchased, at fair value		3	3
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Investments [Abstract]
Investments		62	75
Derivative contracts, at fair value (asset)	[1]	0	0
Assets, Fair Value Disclosure		62	75
Marketable Securities, Equity Securities [Abstract]
Derivative contracts at fair value (liability)	[2]	0	0
Mortgage-backed securities: [Abstract]
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]
Marketable Securities, Equity Securities [Abstract]
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]
Marketable Securities, Equity Securities [Abstract]
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] | Communications [Member]
Marketable Securities, Equity Securities [Abstract]
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]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		0	0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Consumer, cyclical [Member]
Marketable Securities, Equity Securities [Abstract]
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]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		0	0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Energy sector [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		0	0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Financial [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		0	0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Funds [Member]
Marketable Securities, Equity Securities [Abstract]
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]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		0	0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Technology [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		0	0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		62	75
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Consumer, cyclical [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		62	75
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Energy sector [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		0	0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Financial [Member]
Marketable Securities, Equity Securities [Abstract]
Trading Securities		0	0
Investment Segment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Corporate Debt Securities [Member] | Utilities [Member]
Marketable Securities, Equity Securities [Abstract]
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]
Marketable Securities, Equity Securities [Abstract]
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]
Marketable Securities, Equity Securities [Abstract]
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] | Funds [Member]
Marketable Securities, Equity Securities [Abstract]
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.