Stock-based compensation - Effect on shares outstanding and treasury shares (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012		Dec. 31, 2011
Schedule of Changes in Treasury Stock [Line Items]
Treasury stock (in shares)	694,189,127	658,012,970	632,636,970		601,131,631
Repurchases	61,665,209	77,564,013	59,757,780
Total issued (in shares)	(25,481,874)	(52,175,104)	(28,245,849)
Director
Schedule of Changes in Treasury Stock [Line Items]
Issued (in shares)	(7,178)	(12,909)	(6,592)
Employee Stock Option
Schedule of Changes in Treasury Stock [Line Items]
Exercised (in shares)	(19,503,382)	(45,507,711)	(22,409,816)
Previously unissued common shares (in shares)			180,955	[1]
Stock applied to taxes		0	0
Total issued (in shares)	(21,280,948)	(47,894,545)	(25,058,359)
Stock applied to exercises or taxes	6,618
Employee Stock Option | Director
Schedule of Changes in Treasury Stock [Line Items]
Issued (in shares)	0	0	0
Restricted Stock Units (RSUs)
Schedule of Changes in Treasury Stock [Line Items]
Vested RSUs (in shares)	(5,609,627)	(5,741,981)	(4,182,928)
Previously unissued common shares (in shares)			4,593	[1]
Stock applied to taxes		1,461,422	990,845
Total issued (in shares)	(4,200,926)	(4,280,559)	(3,187,490)
Stock applied to exercises or taxes	1,408,701
Restricted Stock Units (RSUs) | Director
Schedule of Changes in Treasury Stock [Line Items]
Issued (in shares)	0	0	0
TI employees 2005 stock purchase plan
Schedule of Changes in Treasury Stock [Line Items]
Exercised (in shares)	(1,784,184)
TI employees 2005 stock purchase plan | Employee Stock Option
Schedule of Changes in Treasury Stock [Line Items]
Exercised (in shares)	(1,784,184)	(2,386,834)	(2,829,498)
TI employees 2005 stock purchase plan | Restricted Stock Units (RSUs)
Schedule of Changes in Treasury Stock [Line Items]
Vested RSUs (in shares)	0	0	0

[1] Beginning in 2013, only treasury shares were issued.