Capital Stock (Narrative) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended						9 Months Ended
	Dec. 22, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Oct. 27, 2020	Dec. 07, 2017
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Dividends Payable, Date to be Paid		Sep. 25, 2020	Jun. 25, 2020	Mar. 27, 2020	Sep. 25, 2019	Jun. 25, 2019	Mar. 29, 2019
Dividends Payable, Date of Record		Sep. 10, 2020	Jun. 10, 2020	Mar. 16, 2020	Sep. 10, 2019	Jun. 10, 2019	Mar. 18, 2019
Increase In Stock Repurchase Program Authorization										$ 5,000
Subsequent Event [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Dividends Payable, Amount Per Share									$ 0.95
Dividends Payable, Date to be Paid	Dec. 22, 2020
Dividends Payable, Date of Record	Dec. 07, 2020
2020 to 2022 [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross								0.3
2017 to 2019 [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross								0.6