Share-Based Incentive Plans (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	$ 51,000,000	$ 48,000,000	$ 39,000,000
Share based compensation related income tax benefits recognized in earnings	9,000,000	$ 16,000,000	$ 14,000,000
Compensation cost not yet recognized	$ 54,000,000
Compensation cost not yet recognized, period for recognition	23 months
Number of shares available for grant (in shares)	6,700,000
Grants in period, weighted average grant date fair value (USD per share)	$ 38.34	$ 44.01	$ 31.21
Weighted average grant date fair value (USD per share)	$ 157.09	$ 164.26	$ 127.88
Total fair value, options vested in period	$ 29,000,000	$ 29,000,000	$ 33,000,000
Nonemployee director equity award	$ 130,000
Nonemployee director one-time shares granted (in shares)	1,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Terms of award	10 years
Intrinsic value	$ 30,000,000	22,000,000	20,000,000
Tax benefit from stock options exercised	7,000,000	8,000,000	7,000,000
Proceeds from stock options exercised	$ 17,000,000	$ 34,000,000	$ 26,000,000
Restricted Stock Units (RSUs) | Management
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Restricted Stock Units (RSUs) | Executives | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Restricted Stock Units (RSUs) | Executives | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	7 years
Performance Stock Units | Management
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Performance Stock Units | Management | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance measures	0.00%
Performance Stock Units | Management | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance measures	200.00%