CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) - $ / shares	3 Months Ended							12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Dividends to common stockholders, per share (in dollars per share)	$ 0.7925	$ 0.7925	$ 0.7925	$ 0.7925	$ 0.79	$ 0.79	$ 0.79	$ 3.17000	$ 3.16250	$ 3.11500