Share-Based Compensation Plans (Details Textual) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Oct. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 26	$ 29	$ 30
Proceeds from exercise of employee stock options	20	$ 13	$ 7
Tax benefit from the exercise of stock options	$ 13
Shares awarded	571
Shares outstanding	1,961	2,040
Non-vested options outstanding	700	600	700
Weighted average grant date fair value	$ 74.00	$ 69.30	$ 58.00
Aggregate intrinsic value of outstanding stock options	$ 89
Aggregate intrinsic value of exercisable stock options	68
Total intrinsic value of options exercised	20	$ 15	$ 9
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized compensation expense	$ 7
Weighted average period	1 year 10 months 24 days
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized compensation expense	$ 21
Weighted average period	1 year 9 months 18 days
Shares awarded	340
Performance Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized compensation expense	$ 6
Weighted average period	1 year 9 months 18 days
Requisite service periods	3 years
Target payout percentage	100.00%
2011 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares initially available for awards				18,000
Shares available for future grant	5,000