Stock-Based Compensation (Stock Based Compensation Textuals) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended							6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013		Jun. 30, 2014 Stock Options [Member]	Jun. 30, 2014 Restricted Stock [Member]	Jun. 30, 2013 Restricted Stock [Member]	Dec. 31, 2013 Restricted Stock [Member]	Jun. 30, 2014 Restricted Stock Units (RSUs) [Member]	Jun. 30, 2014 Performance Shares [Member]	Dec. 31, 2013 Performance Shares [Member]	Jun. 30, 2014 Director Plan [Member]	Jun. 30, 2014 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number							4,692,691		4,431,841		895,879	449,798
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate				1.40%	[1]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate				25.60%	[2]
Vesting period for graded and cliff vesting options - minimum			1 year
Vesting period for graded and cliff vesting options - maximum			5 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Expiration Minimum Range			5 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Expiration Maximum Range			10 years
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized													567,000	40,533,000
Common Stock, Capital Shares Reserved for Future Issuance													186,816	12,501,451
Percentage of sub-grants representing the total	33.33%		33.33%
Vest Term of First Sub Grant			1 year
Vest Term of the Second Sub-Grant			2 years
Vest Term of the Third Sub-Grant			3 years
Grants in Option Grants with Three Year Cliff Vesting			1
Vesting term of option grants with three year cliff vesting			3 years
Allocated Share-based Compensation Expense	$ 8	$ 11	$ 17	$ 19
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized						1	41			1
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition						7 months 29 days	1 year 6 months 5 days			10 months 14 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value			6	4
Employee Service Share-based Compensation, Cash Received from Exercise of Stock Options			15	17
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value							30	21
Allocated Share Based Compensation Expense Liability Classified Share-Based Awards	$ 4	$ 1	$ 5	$ 1
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period							1,842,822				461,393
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value							$ 19.26				$ 22.56

[1] Zero Coupon U.S. Treasury rate or equivalent based on expected term.

[2] Volatility calculated using the implied volatility of our exchange traded stock options.