Financial Instruments - Contractual Maturities (Details) $ in Millions	Dec. 31, 2021 USD ($)
Amortized Cost
Due within one year	$ 39,070
Due after one year through five years	22,790
Due after five years through ten years	2,124
Due after ten years	4,086
Total	68,070
Estimated Fair Value
Due within one year	39,075
Due after one year through five years	22,712
Due after five years through ten years	2,121
Due after ten years	4,073
Total	$ 67,981