Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income
Net actuarial gains (losses) of defined benefit plans adjustment, tax benefit (expense)	$ 6	$ 36	$ 25
Net actuarial gains (losses) of defined benefit plans recognized within Net income, tax benefit (expense)	(25)	(25)	(21)
Prior service (cost) credit of defined benefit plans adjustment, tax benefit (expense)	0	(11)	0
Prior service (cost) credit of defined benefit plans recognized within Net income, tax benefit (expense)	2	0	0
Derivative instruments recognized within Net income, tax benefit (expense)	$ 0	$ (1)	$ (1)