Capital Stock (Stock Repurchases Pursuant To Board Of Director Authorizations) (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity, Class of Treasury Stock [Line Items]
Stock repurchased	9.2	8.7	9.7
Stock repurchase program remaining authorization	0.0
2015 Authorization
Equity, Class of Treasury Stock [Line Items]
Stock repurchased	0.0	0.0	9.0
Stock repurchase program remaining authorization	0.0
2016 Authorization
Equity, Class of Treasury Stock [Line Items]
Stock repurchased	9.2	8.7	0.7
Stock repurchase program remaining authorization	0.0
2018 Authorization
Equity, Class of Treasury Stock [Line Items]
Stock repurchased	0.0	0.0	0.0
Stock repurchase program remaining authorization	0.0