Accumulated Other Comprehensive Income - Components (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	$ (1,898)	$ (3,193)
Other comprehensive income before reclassifications	(46)	66
Amounts reclassified from accumulated other comprehensive income	(2)	4
Other comprehensive income	(48)	70
Balance at end of period	(1,946)	(3,123)
Defined benefit plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(768)	(1,464)
Other comprehensive income before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income	18	30
Other comprehensive income	18	30
Balance at end of period	(750)	(1,434)
Foreign currency translation
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(1,158)	(1,759)
Other comprehensive income before reclassifications	(25)	10
Amounts reclassified from accumulated other comprehensive income	0	0
Other comprehensive income	(25)	10
Balance at end of period	(1,183)	(1,749)
Gains and losses on cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	28	30
Other comprehensive income before reclassifications	(21)	56
Amounts reclassified from accumulated other comprehensive income	(20)	(26)
Other comprehensive income	(41)	30
Balance at end of period	$ (13)	$ 60