Financial Instruments (Contractual Maturity Date of Marketable Debt Securities) (Details) $ in Millions	Mar. 31, 2020 USD ($)
Fair Value Disclosures [Abstract]
Due in 1 year	$ 24,209
Due in 1 year through 5 years	54,662
Due in 5 years through 10 years	3,080
Due after 10 years	12,820
Total	$ 94,771

Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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