Earnings Per Share, Share Repurchases and Dividends on Common Stock (Details 2) - $ / shares shares in Millions	1 Months Ended					12 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2018	Jan. 31, 2018	May 30, 2017	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity, Class of Treasury Stock [Line Items]
Common stock dividend (in dollars per share)	$ 1.45	$ 1.32	$ 1.20	$ 1.10	$ 1.00	$ 5.67	$ 5.16	$ 4.70
Increase (Decrease) in Stock Dividend, Percentage	10.00%		9.00%	10.00%
Earnings Per Share, Basic and Diluted [Abstract]
Dilutive effect of stock options and other stock awards granted						0.5	0.7	0.9
Increase (Decrease) in Stock Dividend, Percentage	10.00%		9.00%	10.00%
Common stock dividend (in dollars per share)	$ 1.45	$ 1.32	$ 1.20	$ 1.10	$ 1.00	$ 5.67	$ 5.16	$ 4.70