Share-Based Associate Compensation Plans (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) compensation_plans shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity compensation plans | compensation_plans	4
Share based compensation	$ 15	$ 14	$ 13
Tax benefit from compensation expense	8	6	6
Options exercised, intrinsic value	25	15	13
Options vested, intrinsic value	11	7	9
Unrecognized compensation costs related to non-vested awards	$ 26
Expected weighted-average period to recognize the unrecognized compensation costs related to non-vested awards	1 year 9 months 18 days
Maximum number of shares awarded to each full-time employee for their service | shares	10
Proceeds from stock options exercised	$ 21	24	22
Shares of common stock granted in period (in shares) | shares	359,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards exercise peirod	10 years
Awards vesting period	3 years
Proceeds from stock options exercised	$ 21	$ 24	$ 22
Shares repurchased | shares	186,097	292,414	378,276
Shares repurchased, value	$ 13	$ 16	$ 19
Weighted average remaining contractual term	8 years 5 months 10 days
Shares authorized to be granted under the shareholder-approved plans | shares	17,300,000
Shares available for future issuance under the plans | shares	13,000,000
Stock Options | Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock granted in period (in shares) | shares	18,769