Capital Stock Capital Stock (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Jul. 17, 2020	Jun. 30, 2020	Feb. 06, 2020	May 08, 2017
Subsequent Event [Line Items]
Shares of common stock authorized (in shares)	100,000,000		100,000,000
Shares issued and outstanding (in shares)	50,100,000		50,500,000
Maximum shares allowed for issuance (in shares)			2,000,000.0
Par value (in dollars per share)			$ 10
250 Million Share Repurchase Program
Subsequent Event [Line Items]
Stock repurchase program amount				$ 250,000,000
200 Million Share Repurchase Program
Subsequent Event [Line Items]
Stock repurchase program amount					$ 200,000,000
Stock repurchased and retired during period, shares	1,300,000
Stock repurchase program amount used	$ 94,000,000
Average price per share (in dollars per share)	$ 69.35
Stock repurchase program remaining amount			$ 106,000,000
Subsequent Event
Subsequent Event [Line Items]
Dividends declared (in dollars per share)		$ 0.15