Capital Stock (Narrative) (Details) (USD $)	3 Months Ended				12 Months Ended			1 Months Ended	2 Months Ended	0 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 05, 2015	Mar. 25, 2015	Feb. 04, 2014	Oct. 02, 2014	Jan. 27, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation cost					$ 168,900,000	$ 146,000,000	$ 146,500,000
Tax benefit from share-based compensation expense					60,700,000	52,600,000	52,000,000
Employee stock purchase plan, purchase price per share as a percent of closing price					95.00%
Common stock purchased under Stock Purchase Plan					0	0	0
Cash dividend payment date	Dec. 22, 2014	Sep. 25, 2014	Jun. 25, 2014	Mar. 25, 2014
Cash dividend record date	Dec. 05, 2014	Sep. 10, 2014	Jun. 10, 2014	Mar. 10, 2014
Increase in stock repurchase program authorization											5,000,000,000.0
Accelerated share repurchase program, shares repurchased					30,400,000	20,700,000
Incentive Compensation Plan [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Number of registered shares for issuance	60,100,000				60,100,000
Common stock available for future issuance	21,200,000				21,200,000
Restricted Stock Units (RSUs) [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Fair value of shares vested					174,000,000	46,700,000	222,300,000
Approximate number of performance restricted stock units granted					700,000
Approximate number of performance restricted stock units earned	1,000,000				1,000,000
Unrecognized compensation cost related to restricted stock	76,900,000				76,900,000
Weighted-average remaining requisite service period, months					10 months
Stock Option [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock incentive plan vesting period, years					3 years
Stock option term, years					7 years
Intrinsic value of options exercised					156,700,000	176,000,000	65,400,000
Tax benefit from stock option exercises and disqualifying dispositions					53,200,000	56,800,000	22,900,000
Cash received from exercise of stock options					283,600,000	524,700,000	110,800,000
Unrecognized compensation cost related to restricted stock	14,000,000				14,000,000
Weighted-average remaining requisite service period, months					11 months
Subsequent Event [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Cash Dividend per Share												$ 0.6250
Cash dividend payment date									Mar. 25, 2015
Cash dividend record date									Mar. 10, 2015
Accelerated share repurchase program, shares repurchased								1,800,000
Employee Stock Purchase Plan [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Number of registered shares for issuance	14,000,000				14,000,000
Common stock available for future issuance	5,900,000				5,900,000
Maximum amount of stock employees are permitted to purchase per calender year					25,000
Payroll deductions, percent of gross compensation, minimum	1.00%				1.00%
Payroll deductions, percent of gross compensation, maximum	15.00%				15.00%
Employee stock purchase plan, purchase price per share as a percent of closing price					95.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans					200,000
Call Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Number of shares subject to purchase call options					3,000,000
Aggregate premium paid					25,800,000
Aggregate fair value	27,500,000				27,500,000
Call Options [Member] | Minimum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Price per share	77.50				$ 77.50
Call Options [Member] | Maximum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Price per share	83.10				$ 83.10
Shareholders' Equity [Member] | Call Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Aggregate premium paid					7,900,000
Derivative assets [Member] | Call Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Aggregate premium paid					17,900,000
Repurchase Agreements [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Accelerated share repurchase program, amount authorized										$ 600,000,000.0
Accelerated share repurchase program, shares repurchased						6,600,000