Earnings Per Share, Share Repurchases and Dividends on Common Stock (Unaudited) Earnings Per Share and Dividends (Details 1) - $ / shares shares in Millions	1 Months Ended		3 Months Ended		6 Months Ended
	May 31, 2021	May 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share, Basic and Diluted [Abstract]
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements			0.5	0.4	0.5	0.6
Common stock dividends per share, declared (in dollars per share)	$ 1.57	$ 1.45			$ 3.02	$ 2.77
Increase in quarterly common stock dividend (percent)	8.00%