Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2020		Jun. 30, 2019		Jun. 30, 2020		Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total Other comprehensive income (loss), net of tax	$ 61		$ 36		$ (260)		$ 69
Cumulative translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), pretax	27		23		(293)		50
Total Other comprehensive income (loss), net of tax	65		30		(274)		51
Retirement plans and other retiree benefits adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), pretax	23		18		42		34
Other comprehensive income (loss), before reclassifications, pretax	0		0		2		(1)
Reclassification from AOCI, pretax	23		18		40		35
Other comprehensive income (loss), before reclassifications, net of tax	0		0		1		(1)
Reclassification from AOCI, net of tax	14		13		29		26
Total Other comprehensive income (loss), net of tax	14		13		30		25
Gains (losses) on cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), pretax	(25)		(2)		(3)		(8)
Other comprehensive income (loss), before reclassifications, pretax	(22)		(1)		3		(3)
Reclassification from AOCI, pretax	(3)		(1)		(6)		(5)
Other comprehensive income (loss), before reclassifications, net of tax	(18)		(1)		2		(3)
Reclassification from AOCI, net of tax	(3)		(1)		(5)		(4)
Total Other comprehensive income (loss), net of tax	(21)		(2)		(3)		(7)
Total Other comprehensive income (loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), pretax	25		39		(254)		76
Total Other comprehensive income (loss), net of tax	$ 58	[1]	$ 41	[1]	$ (247)	[2]	$ 69	[2]

[1] Accumulated other comprehensive income (loss) includes cumulative translation losses of $3,402 at June 30, 2020 ($3,104 at June 30, 2019) and $3,467 at March 31, 2020 ($3,134 at March 31, 2019), respectively, and unrecognized retirement plan and other retiree benefits costs of $1,108 at June 30, 2020 ($1,013 at June 30, 2019) and $1,122 at March 31, 2020 ($1,026 at March 31, 2019), respectively.

[2] Accumulated other comprehensive income (loss) includes cumulative translation losses of $3,402 at June 30, 2020 ($3,104 at June 30, 2019) and $3,128 at December 31, 2019 ($3,155 at December 31, 2018), respectively, and unrecognized retirement plan and other retiree benefits costs of $1,108 at June 30, 2020 ($1,013 at June 30, 2019) and $1,138 at December 31, 2019 ($1,038 at December 31, 2018), respectively.