Supplemental Information (Earnings Per Share) (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share Reconciliation [Abstract]
Weighted-average Common Shares Outstanding - Basic (in shares)	245,600,000	243,800,000	242,600,000
Assumed settlement of performance share units and restricted stock units (in shares)	1,400,000	2,000,000.0	1,600,000
Dilutive effect of forward sale agreement (in shares)	100,000	0	0
Weighted Average Number of Shares Outstanding, Diluted (in shares)	247,100,000	245,800,000	244,200,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)	0	0	0