Common Stock - Shares Issued (Details) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Increase (Decrease) in Common Stock Shares
Total issued - balance at January 1 (shares)	4,104,933,895	4,104,933,895	4,104,900,000
Total issued - balance at December 31 (shares)	4,104,933,895	4,104,933,895	4,104,933,895
Increase (Decrease) in Treasury Stock Shares
Treasury - balance at January 1 (in shares)	(390,144,630)
Issuance of shares for warrant exercise (in shares)	4,700,000	0	0
Total treasury - balance at December 31 (in shares)	(441,459,392)	(390,144,630)
Outstanding (in shares)	3,663,500,000	3,714,800,000	3,756,100,000
Treasury stock, at cost
Increase (Decrease) in Treasury Stock Shares
Treasury - balance at January 1 (in shares)	(390,100,000)	(348,800,000)	(300,900,000)
Purchase of treasury stock (in shares)	(89,800,000)	(82,300,000)	(96,100,000)
Issued from treasury (in shares)	38,500,000	41,000,000	48,200,000
Issued from treasury: Employee stock purchase plans (in shares)	1,000,000	1,200,000	1,100,000
Total treasury - balance at December 31 (in shares)	(441,400,000)	(390,100,000)	(348,800,000)
Treasury stock, at cost | Stock Compensation Plan
Increase (Decrease) in Treasury Stock Shares
Issued from treasury (in shares)	32,800,000	39,800,000	47,100,000