Capital Stock (Schedule of Issued Repurchased and Outstanding Shares) (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Common Stock, Shares Outstanding [Roll Forward]
Beginning balance, Shares Issued (in shares)	2,805,961,317	2,805,961,317	2,805,961,317
Beginning balance, Shares Repurchased (in shares)	(931,903,722)	(904,702,125)	(862,689,093)
Beginning balance, Shares Outstanding (in shares)	1,874,057,595	1,901,259,192	1,943,272,224
Stock award activity (in shares)	427,276	676,727	(408,891)
Repurchases of common stock (in shares)	(16,503,317)	(27,878,324)	(41,604,141)
Ending balance, Shares Issued (in shares)	2,805,961,317	2,805,961,317	2,805,961,317
Ending balance, Shares Repurchased (in shares)	(947,979,763)	(931,903,722)	(904,702,125)
Ending balance, Shares Outstanding (in shares)	1,857,981,554	1,874,057,595	1,901,259,192