Statement of Changes in Consolidated Equity (unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Common stock, dividends per share (in usd per share)	$ 0.12	$ 0.12
Preferred Class A
Preferred, dividends per share (in usd per share)	$ 0.9375	0.9375
Preferred Class B
Preferred, dividends per share (in usd per share)		$ 6.71876