Investment Securities (Investment Table) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Schedule of Investments [Line Items]
Debt securities, available-for-sale, fair value	$ 29,830	$ 30,284
Debt securities, held-to-maturity, amortized cost	1,253	1,568
Held-to-maturity securities, fair value	1,331	1,600
Available-for-sale securities
Schedule of Investments [Line Items]
Securities pledged for Federal Home Loan Bank, at fair value	145	1,900
Securities, amount eligible to be repledged or sold by counterparty	145	118
Operating Segments \| Insurance operations \| Available-for-sale securities
Schedule of Investments [Line Items]
Deposit securities	13	12
US Treasury \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	783	2,059
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	20	6
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0	(17)
Debt securities, available-for-sale, fair value	803	2,048
US States and political subdivisions \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	1,046	623
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	50	19
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	(1)	(1)
Debt securities, available-for-sale, fair value	1,095	641
Foreign government \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	167	184
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	9	3
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0	(1)
Debt securities, available-for-sale, fair value	176	186
Agency mortgage-backed residential
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	1,253
Agency mortgage-backed residential \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	18,053	21,183
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	538	257
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	(3)	(36)
Debt securities, available-for-sale, fair value	18,588	21,404
Agency mortgage-backed residential \| Held-to-maturity securities
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	1,253	1,547
Debt securities, held-to-maturity, unrecognized gain	79	38
Debt securities, held-to-maturity, unrecognized loss	(1)	(6)
Held-to-maturity securities, fair value	1,331	1,579
Mortgage-backed residential \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	2,595	2,841
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	49	20
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	(4)	(11)
Debt securities, available-for-sale, fair value	2,640	2,850
Agency mortgage-backed commercial \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	4,063	1,344
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	139	44
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	(13)	(6)
Debt securities, available-for-sale, fair value	4,189	1,382
Mortgage-backed commercial \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	0	41
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	0	1
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0	0
Debt securities, available-for-sale, fair value	0	42
Asset-backed \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	420	365
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	5	3
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0	0
Debt securities, available-for-sale, fair value	425	368
Asset-backed \| Held-to-maturity securities
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	0	21
Debt securities, held-to-maturity, unrecognized gain	0	0
Debt securities, held-to-maturity, unrecognized loss	0	0
Held-to-maturity securities, fair value	0	21
Corporate debt \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	1,809	1,327
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	105	37
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0	(1)
Debt securities, available-for-sale, fair value	1,914	1,363
Available-for-sale debt securities \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	28,936	29,967
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	915	390
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	(21)	(73)
Debt securities, available-for-sale, fair value	29,830	30,284
Accrued interest receivable	90	98
Held-to-maturity securities
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	1,253	1,568
Debt securities, held-to-maturity, unrecognized gain	79	38
Debt securities, held-to-maturity, unrecognized loss	(1)	(6)
Held-to-maturity securities, fair value	1,331	1,600
Accrued interest receivable	3	3
Federal Home Loan Bank certificates and obligations \| Held-to-maturity securities
Schedule of Investments [Line Items]
Securities pledged for Federal Home Loan Bank, at fair value	$ 0	$ 915

Interest, dividends, rents, ancillary and other revenues earned but not yet received by the entity on its investments.

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