Investment Securities (Investment Table) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Schedule of Investments [Line Items]
Debt securities, available-for-sale, fair value	$ 29,225	$ 30,284
Debt securities, held-to-maturity, amortized cost	1,390	1,568
Held-to-maturity securities, fair value	1,476	1,600
Available-for-sale securities
Schedule of Investments [Line Items]
Securities pledged for Federal Home Loan Bank, at fair value	215	1,900
Securities, amount eligible to be repledged or sold by counterparty	215	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	784	2,059
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	23	6
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0	(17)
Debt securities, available-for-sale, fair value	807	2,048
US States and political subdivisions \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	876	623
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	38	19
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	(1)	(1)
Debt securities, available-for-sale, fair value	913	641
Foreign government \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	153	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	162	186
Agency mortgage-backed residential
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	1,376
Agency mortgage-backed residential \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	19,136	21,183
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	752	257
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	(4)	(36)
Debt securities, available-for-sale, fair value	19,884	21,404
Agency mortgage-backed residential \| Held-to-maturity securities
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	1,376	1,547
Debt securities, held-to-maturity, unrecognized gain	86	38
Debt securities, held-to-maturity, unrecognized loss	0	(6)
Held-to-maturity securities, fair value	1,462	1,579
Mortgage-backed residential \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	3,387	2,841
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	42	20
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	(4)	(11)
Debt securities, available-for-sale, fair value	3,425	2,850
Agency mortgage-backed commercial \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	1,647	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	0	(6)
Debt securities, available-for-sale, fair value	1,786	1,382
Mortgage-backed commercial \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	41	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	(3)	0
Debt securities, available-for-sale, fair value	38	42
Asset-backed
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	14
Asset-backed \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	352	365
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	4	3
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	0	0
Debt securities, available-for-sale, fair value	356	368
Asset-backed \| Held-to-maturity securities
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	14	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	14	21
Corporate debt \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	1,761	1,327
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	97	37
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	(4)	(1)
Debt securities, available-for-sale, fair value	1,854	1,363
Available-for-sale debt securities \| Available-for-sale securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale, amortized cost	28,137	29,967
Debt securities, available-for-sale, accumulated gross unrealized gain, before tax	1,104	390
Debt securities, available-for-sale, accumulated gross unrealized loss, before tax	(16)	(73)
Debt securities, available-for-sale, fair value	29,225	30,284
Accrued interest receivable	90	98
Held-to-maturity securities
Schedule of Investments [Line Items]
Debt securities, held-to-maturity, amortized cost	1,390	1,568
Debt securities, held-to-maturity, unrecognized gain	86	38
Debt securities, held-to-maturity, unrecognized loss	0	(6)
Held-to-maturity securities, fair value	1,476	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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