CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 544	$ 366	$ 1,525	$ 1,057
Items related to employee benefit plans:
Change in net actuarial loss, net of $(69), $(12), $(93) and $(37) tax	214	38	290	115
Change in net prior service cost, net of $—, $—, $(1) and $(1) tax	1	1	3	4
Curtailment loss, net of $—, $(1), $— and $(1) tax	0	3	0	3
Reclassification of realized loss on interest rate swaps to net income, net of $(5), $(5), $(15) and $(10) tax	16	15	47	31
Unrealized holding (loss) gain on interest rate swaps, net of $—, $—, $— and $28 tax	(1)	1	(1)	(87)
Foreign currency translation adjustment, net of $13, $(21), $16 and $(2) tax	(97)	49	(103)	(181)
Other comprehensive income (loss)	133	107	236	(115)
COMPREHENSIVE INCOME	$ 677	$ 473	$ 1,761	$ 942