Capital Stock (Schedule of Shares Repurchased) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2019	Oct. 31, 2021	Jan. 31, 2021	Dec. 31, 2020	Jul. 31, 2019	May 31, 2018	Jan. 31, 2018
Class of Stock [Line Items]
Total number of shares repurchased (in shares)	35,656,116	16,503,317
Aggregate cost of shares repurchased	$ 1,675,000,000	$ 845,000,000
Average price per share of shares repurchased (USD per share)		$ 51.24
Stock repurchase program, authorized amount					$ 0
January 2021 Share Repurchase Program [Member]
Class of Stock [Line Items]
Total number of shares repurchased (in shares)	35,700,000
Aggregate cost of shares repurchased	$ 1,675,000,000
Average price per share of shares repurchased (USD per share)	$ 46,970,000
Stock repurchase program, authorized amount			$ 3,500,000,000	$ 2,000,000,000
July 2019 Share Repurchase Program [Member]
Class of Stock [Line Items]
Total number of shares repurchased (in shares)		10,100,000
Aggregate cost of shares repurchased		$ 500,000,000
Average price per share of shares repurchased (USD per share)		$ 49,290,000
Stock repurchase program, authorized amount						$ 1,000,000,000
January 2018 Share Repurchase Program [Member]
Class of Stock [Line Items]
Total number of shares repurchased (in shares)		6,400,000
Aggregate cost of shares repurchased		$ 345,000,000
Average price per share of shares repurchased (USD per share)		$ 54,360,000
Stock repurchase program, authorized amount							$ 2,000,000,000	$ 1,000,000,000