Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Consolidated Statements of Comprehensive Income Parenthetical [Abstract]
Unrecognized amounts on retirement benefits, tax	$ 7	$ 7	$ 26	$ 4
Unrealized (losses) gains on available-for-sale securities, tax	53	(69)	89	121
Unrealized (losses) gains on cash flow hedges, tax	$ (3)	$ (6)	$ (1)	$ (9)