Acquisitions (2015 Acquisitions Dorsey, Wright & Associates) (Narrative) (Details) - USD ($) $ in Millions		1 Months Ended	2 Months Ended	12 Months Ended
	Jan. 30, 2015	Jan. 31, 2015	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2013	Dec. 31, 2014	Jun. 28, 2013
Business Acquisition [Line Items]
Business acquisition, working capital adjustments					$ 484
Acquired intangible assets				$ 141	715
Goodwill				5,395		$ 5,538
Credit facility, proceeds				$ 406
Trade names [Member]
Business Acquisition [Line Items]
Acquired intangible assets							$ 578
Technology [Member]
Business Acquisition [Line Items]
Acquired intangible assets					16		16
Estimated Average Remaining Useful Life				5 years
Customer Relationships [Member]
Business Acquisition [Line Items]
Acquired intangible assets					$ 121		$ 121
Estimated Average Remaining Useful Life				15 years
Dorsey, Wright & Associates, LLC or DWA [Member]
Business Acquisition [Line Items]
Purchase consideration	$ 226			$ 226
Business acquisition, cash paid	225
Net assets Acquired	8
Business acquisition, working capital adjustments	1
Net liabilities assumed	26
Acquired intangible assets				141
Goodwill				$ 111
Deferred Tax Liabilities Noncurrent	33
Deferred Tax Liabilities Current	$ 1
Dorsey, Wright & Associates, LLC or DWA [Member] | Revolving Credit Facility [Member]
Business Acquisition [Line Items]
Credit facility, proceeds		$ 100	$ 100
Dorsey, Wright & Associates, LLC or DWA [Member] | Trade names [Member] | Income Approach Valuation Technique [Member]
Business Acquisition [Line Items]
Discount rate				17.00%
Discounted cash flows tax effect				36.50%
Amortization period of intangible assets for tax purposes				15 years
Dorsey, Wright & Associates, LLC or DWA [Member] | Technology [Member] | Income Approach Valuation Technique [Member]
Business Acquisition [Line Items]
Discount rate				17.00%
Discounted cash flows tax effect				36.50%
Amortization period of intangible assets for tax purposes				15 years
Pre tax royalty rate				15.00%
Dorsey, Wright & Associates, LLC or DWA [Member] | Customer Relationships [Member] | Income Approach Valuation Technique [Member]
Business Acquisition [Line Items]
Discount rate				17.50%
Premium rate				0.50%
Discounted cash flows tax effect				36.50%
Amortization period of intangible assets for tax purposes				15 years
Customer relationships intangible assets, estimated percentage of revenues				100.00%
Dorsey, Wright & Associates, LLC or DWA [Member] | Maximum [Member] | Technology [Member]
Business Acquisition [Line Items]
Royalty rate, profit split				30.00%
Dorsey, Wright & Associates, LLC or DWA [Member] | Maximum [Member] | Customer Relationships [Member] | Income Approach Valuation Technique [Member]
Business Acquisition [Line Items]
Customer relationships intangible assets, period of growth				6 years
Dorsey, Wright & Associates, LLC or DWA [Member] | Minimum [Member] | Technology [Member]
Business Acquisition [Line Items]
Royalty rate, profit split				25.00%
Dorsey, Wright & Associates, LLC or DWA [Member] | Minimum [Member] | Customer Relationships [Member] | Income Approach Valuation Technique [Member]
Business Acquisition [Line Items]
Customer relationships intangible assets, period of growth				3 years