Supplemental Information (Earnings Per Share) (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share Reconciliation [Abstract]
Weighted-average Common Shares Outstanding – Basic	247,100,000	245,900,000	246,800,000	245,500,000
Assumed settlement of performance share units and restricted stock units	1,500,000	1,400,000	1,200,000	1,400,000
Dilutive effect of forward sale agreement	600,000	200,000	400,000	100,000
Weighted-average Common Shares Outstanding – Diluted	249,200,000	247,500,000	248,400,000	247,000,000.0
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)	0	0	0	0