Capital Stock (Schedule of Issued Repurchased and Outstanding Shares) (Details) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
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)	(845,901,836)	(834,486,794)	(812,482,035)
Beginning balance, Shares Outstanding (in shares)	1,960,059,481	1,971,474,523	1,993,479,282
Stock award activity (in shares)	(566,256)	(732,623)	447,840
Repurchases of common stock (in shares)	(16,221,001)	(10,682,419)	(22,452,599)
Ending balance, Shares Issued (in shares)	2,805,961,317	2,805,961,317	2,805,961,317
Ending balance, Shares Repurchased (in shares)	(862,689,093)	(845,901,836)	(834,486,794)
Ending balance, Shares Outstanding (in shares)	1,943,272,224	1,960,059,481	1,971,474,523