Capital Stock (Narrative) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions			3 Months Ended				6 Months Ended
	Sep. 25, 2019	Sep. 10, 2019	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Dec. 07, 2017
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Dividends Payable, Date to be Paid			Jun. 25, 2019	Mar. 29, 2019	Jun. 25, 2018	Mar. 23, 2018
Dividends Payable, Date of Record			Jun. 10, 2019	Mar. 18, 2019	Jun. 08, 2018	Mar. 09, 2018
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	$ 0.80
Dividends Payable, Date to be Paid	Sep. 25, 2019
Dividends Payable, Date of Record		Sep. 10, 2019
2019 to 2021 [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							0.2