Investment Securities (Details 3) $ in Millions	Mar. 31, 2019 USD ($)
Available For Sale Securities Debt Maturities Amortized Cost [Abstract]
Due within 1 year	$ 4,599
Due after 1 year but within 5 years	1,315
Due after 5 years but within 10 years	179
Due after 10 years	305
Total	6,398
Estimated Fair Value
Estimated Fair Value, Due within 1 year	4,600
Estimated Fair Value, Due after 1 year but within 5 years	1,319
Estimated Fair Value, Due after 5 years but within 10 years	181
Estimated Fair Value, Due after 10 years	310
Total	$ 6,410

Amortized cost 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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