Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash dividends declared
Common stock, dividend per share (in dollars per share)	$ 1.64	$ 1.48	$ 1.34
Series B [Member]
Cash dividends declared
Preferred stock, dividend per share (in dollars per share)	52.00	52.00	52.00
Series C [Member]
Cash dividends declared
Preferred stock, dividend per share (in dollars per share)	$ 49.00	$ 49.00	$ 49.00