Changes in and Reclassification out of Accumulated Other Comprehensive Income/(Loss) by Component - Summary of Reclassification of Accumulated Other Comprehensive Loss by Component (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive (income)/loss	$ 381	$ 4
Connect
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive (income)/loss	374
Currency Translation Adjustments | Connect
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive (income)/loss	233
Unrealized (Gains)/Losses on Pension Liability on Dispositions | Connect
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive (income)/loss	$ 141