Commitments and Contingencies Commitments and Contingencies (Details) In Millions, unless otherwise specified	12 Months Ended				12 Months Ended				1 Months Ended	12 Months Ended
	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Nov. 11, 2013 Entity	Dec. 31, 2014 Licensing Agreements [Member] USD ($)	Dec. 31, 2013 Licensing Agreements [Member] USD ($)	Dec. 31, 2012 Licensing Agreements [Member] USD ($)	Dec. 31, 2014 NYSE AMEX OPTIONS [Member] USD ($)	Jul. 31, 2014 NYSE AMEX OPTION [Member] [Member] USD ($)	Dec. 31, 2014 ATG ATS and NYSE BV Arbitration [Member] Minimum [Member] USD ($)	Dec. 31, 2014 ATG ATS and NYSE BV Arbitration [Member] Minimum [Member] BRL	Dec. 31, 2014 ATG Ownership Percentage in ATS [Member] ATG ATS and NYSE BV Arbitration [Member]	Dec. 31, 2014 NYSE BV Ownership Percentage in ATS [Member] ATG ATS and NYSE BV Arbitration [Member]
Other Commitments [Line Items]
Equity Method Investmetn, Ownership Percentage by External Investors												80.00%
Loss Contingency, Damages Sought, Value										$ 38	100
Exchange Rate, Brazilian Real to USD	0.3763
Other intangible assets, net	7,780	9,323	799		48	67
Amortization Of Other Intangible Assets					19
License Agreement Current Liabilities					19	19
License Agreement Noncurrent Liabilities					32	48
License Agreement Interest Expenses					3	4	5
Call and Put Options Exercisable Triggering Period	2 years
Call and Put Option Expiration Period	5 years
Redeemable Noncontrolling Interest, Equity, Fair Value	16							125
Equity Method Investment, Ownership Percentage													20.00%
Operating Leases, Rent Expense	82	47	23
Number of US Options Exchanges				2
Number of External Investors, Significant Equity Interest Sold				7
Payments for Repurchase of Redeemable Noncontrolling Interest									$ 128