Equity and Comprehensive Income - Comprehensive Income (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of year	$ 69,272	$ 62,835
Other comprehensive income (loss)	(1,467)	1,140	$ (675)
Amounts reclassified to net income	611	(2,209)	(697)
Net other comprehensive income (loss)	(856)	(1,069)	(1,372)
Balance at end of year	83,200	69,272	62,835
Foreign currency translation adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of year	(404)	(584)	(600)
Other comprehensive income (loss)	(141)	180	16
Amounts reclassified to net income	0	0	0
Net other comprehensive income (loss)	(141)	180	16
Balance at end of year	(545)	(404)	(584)
Unrealized gains (losses) on cash flow hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of year	(1,387)	(816)	(80)
Other comprehensive income (loss)	(1,318)	953	(699)
Amounts reclassified to net income	1,233	(1,524)	(37)
Net other comprehensive income (loss)	(85)	(571)	(736)
Balance at end of year	(1,472)	(1,387)	(816)
Unrealized gains (losses) on marketable securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of year	25	27	20
Other comprehensive income (loss)	(8)	7	8
Amounts reclassified to net income	(1)	(9)	(1)
Net other comprehensive income (loss)	(9)	(2)	7
Balance at end of year	16	25	27
Defined benefit pension and postretirement plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of year	1,695	2,371	3,030
Other comprehensive income (loss)	0	0	0
Amounts reclassified to net income	(621)	(676)	(659)
Net other comprehensive income (loss)	(621)	(676)	(659)
Balance at end of year	1,074	1,695	2,371
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of year	(71)	998	2,370
Net other comprehensive income (loss)	(856)	(1,069)	(1,372)
Balance at end of year	$ (927)	$ (71)	$ 998