Equity Incentive Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity Incentive Plans
Compensation expense	$ 88,000,000	$ 93,000,000	$ 86,000,000
Share-based compensation arrangement by share-based payment award, recognized tax benefits	30,000,000	32,000,000	30,000,000
Cash received from the exercise of options	314,000,000	212,000,000	99,000,000
Tax benefit realized on options exercised and stock unrestricted	73,000,000	65,000,000	28,000,000
Equity Incentive Plans
Unrecognized compensation cost related to nonvested awards	74,000,000
Tax (expense) benefit realized related to all stock-based compensation included in shareholder's equity	32,000,000	30,000,000	6,000,000
Common stock authorized for stock-based awards (in shares)	97,600,000
Common stock reserved for further issuance (in shares)	29,700,000
Stock options
Equity Incentive Plans
Tax (expense) benefit realized related to all stock-based compensation included in shareholder's equity	23,000,000	12,000,000	8,000,000
Vesting period of options granted prior to 2010	3 years
Portion of awards vesting and unrestricting on second anniversary of grant date (as a percent)	50.00%
Portion of awards vesting and unrestricting on third and fourth anniversaries of grant date (as a percent)	25.00%
Expiration term for options	10 years
Assumptions used to determine fair value of options granted
Weighted average expected term	6 years 6 months	8 years 2 months 12 days	9 years
Expected volatility, low end of the range (as a percent)	16.80%	19.10%	20.20%
Expected volatility, high end of the range (as a percent)	42.20%	48.10%	53.90%
Weighted average volatility (as a percent)	28.30%	31.00%	34.60%
Expected dividends, minimum range (as a percent)	1.70%	1.90%	2.20%
Expected dividends, maximum range (as a percent)	2.20%	2.20%	3.00%
Weighted average expected dividends (as a percent)	2.10%	2.20%	2.80%
Risk-free rate, low end of the range (as a percent)	0.00%	0.00%	0.00%
Risk-free rate, high end of the range (as a percent)	3.00%	2.90%	2.20%
Stock option activity
Outstanding at the beginning of the period (in shares)	23,982,000
Granted (in shares)	2,499,000
Exercised (in shares)	(7,750,000)
Forfeited (in shares)	(535,000)
Expired (in shares)	(207,000)
Outstanding at the end of the period (in shares)	17,989,000	23,982,000
Outstanding, net of expected forfeitures (in shares)	17,856,000
Outstanding, exercisable ("vested") (in shares)	10,872,000
Outstanding at the beginning of the period (in dollars per share)	$ 40.60
Granted (in dollars per share)	$ 52.43
Exercised (in dollars per share)	$ 40.55
Forfeited (in dollars per share)	$ 41.67
Expired (in dollars per share)	$ 56.44
Outstanding at the end of the period (in dollars per share)	$ 42.05	$ 40.60
Outstanding, net of expected forfeitures (in dollars per share)	$ 42.02
Outstanding, exercisable ("vested") (in dollars per share)	$ 41.19
Aggregate intrinsic value, Outstanding	507,227,000
Aggregate intrinsic value, net of expected forfeitures, outstanding	504,113,000
Aggregate intrinsic value, exercisable ("vested"), outstanding	315,929,000
Weighted average remaining contractual term, Outstanding	5 years 4 months 24 days
Weighted average remaining contractual term, net of expected forfeitures, outstanding	5 years 4 months 24 days
Weighted average remaining contractual term, exercisable ("vested"), outstanding	3 years 9 months 18 days
Weighted average grant date fair value of options granted (in dollars per share)	$ 12.50	$ 11.99	$ 8.69
Intrinsic value of options exercised	151,000,000	92,000,000	52,000,000
Nonqualified stock options
Equity Incentive Plans
Unrecognized compensation cost related to nonvested awards	29,000,000
Expected period of recognition of unrecognized compensation cost	1 year 9 months 11 days
Restricted stock units
Equity Incentive Plans
Unrecognized compensation cost related to nonvested awards	34,000,000
Expected period of recognition of unrecognized compensation cost	1 year 9 months 22 days
Portion of awards vesting and unrestricting on second anniversary of grant date (as a percent)	50.00%
Portion of awards vesting and unrestricting on third and fourth anniversaries of grant date (as a percent)	25.00%
Stock units activity
Outstanding at the beginning of the period (in shares)	2,840,000
Granted (in shares)	755,000
Vested (in shares)	(1,098,000)
Forfeited (in shares)	(217,000)
Outstanding at the end of the period (in shares)	2,280,000	2,840,000
Weighted average grant date fair value, nonvested at the beginning of the period (in dollars per share)	$ 35.89
Weighted average grant date fair value, granted (in dollars per share)	$ 52.70	$ 45.78	$ 31.89
Weighted average grant date fair value, vested (in dollars per share)	$ 32.07
Weighted average grant date fair value, forfeited (in dollars per share)	$ 42.46
Weighted average grant date fair value, nonvested at the end of the period (in dollars per share)	$ 42.71	$ 35.89
Total fair value of restricted stock and restricted stock units vested	60,000,000	104,000,000	30,000,000
Performance stock awards
Equity Incentive Plans
Unrecognized compensation cost related to nonvested awards	$ 11,000,000
Expected period of recognition of unrecognized compensation cost	1 year 4 months 17 days
Stock units activity
Outstanding at the beginning of the period (in shares)	843,000
Granted (in shares)	259,000
Adjustment for performance achievement (in shares)	240,000
Vested (in shares)	0	0	0
Forfeited (in shares)	(38,000)
Outstanding at the end of the period (in shares)	1,304,000	843,000
Weighted average grant date fair value, nonvested at the beginning of the period (in dollars per share)	$ 36.38
Weighted average grant date fair value, granted (in dollars per share)	$ 52.18	$ 45.61	$ 31.41
Weighted average grant date fair value, adjustment for performance achievement (in dollars per share)	$ 37.35
Weighted average grant date fair value, forfeited (in dollars per share)	$ 36.41
Weighted average grant date fair value, nonvested at the end of the period (in dollars per share)	$ 39.70	$ 36.38