Stockholders' Equity (Components of Accumulated Other Comprehensive Income) (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net current period other comprehensive income (loss)		$ 125	$ (4)	$ (274)	$ 22
Net current period other comprehensive income (loss)		$ 5	$ 26	39	22
Dividends declared		$ 1.07	$ 1.03
Defined Benefit Pension Plans
Defined benefit and other postretirement benefit plans - Beginning balance				(979)	(1,017)
Other comprehensive income/(loss) before reclassifications				22	1
(Income)/loss reclassified from AOCI	[1]			16	6
Net current period other comprehensive income (loss)				38	7
Defined benefit and other postretirement benefit plans - Ending balance		$ (941)	$ (1,010)	(941)	(1,010)
Other Postretirement Benefit Plans
Defined benefit and other postretirement benefit plans - Beginning balance				(13)	12
Other comprehensive income/(loss) before reclassifications				2	15
(Income)/loss reclassified from AOCI	[1]			(1)	(1)
Net current period other comprehensive income (loss)				1	14
Defined benefit and other postretirement benefit plans - Ending balance		(12)	26	(12)	26
Unrealized Translation
Unrealized translation - Beginning balance				(2,271)	(2,297)
Other comprehensive income/(loss) before reclassifications				(266)	29
(Income)/loss reclassified from AOCI				0	0
Net current period other comprehensive income (loss)				(266)	29
Unrealized translation - Ending balance		(2,537)	(2,268)	(2,537)	(2,268)
Cash Flow Hedges and Other
Cash flow hedge and other - Beginning balance				(31)	3
Other comprehensive income/(loss) before reclassifications				17	(12)
(Income)/loss reclassified from AOCI				(9)	(8)
Net current period other comprehensive income (loss)				8	(20)
Cash flow hedge and other - Ending balance		$ (23)	$ (17)	$ (23)	$ (17)

[1] Included in computation of net periodic benefit costs.