Investments (HTM Year of Issuance) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Schedule of Held-to-maturity Securities [Line Items]
2021	$ 102
2020	124
2019	10
2018	0
2017	8
Prior	197
Held-to-maturity	$ 441	$ 636

Amount excluding accrued interest, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

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Amount excluding accrued interest of investment in debt security measured at amortized cost (held-to-maturity) originated more than five years prior to current fiscal year.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919232-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=124255953&loc=SL120267963-210447

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Amount excluding accrued interest of investment in debt security measured at amortized cost (held-to-maturity) originated four years prior to current fiscal year.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 3B
-URI http://asc.fasb.org/extlink&oid=124255953&loc=SL120267963-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Topic 326
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-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919232-210447

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Amount excluding accrued interest of investment in debt security measured at amortized cost (held-to-maturity) originated three years prior to current fiscal year.

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Amount excluding accrued interest of investment in debt security measured at amortized cost (held-to-maturity) originated in current fiscal year.

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Amount excluding accrued interest of investment in debt security measured at amortized cost (held-to-maturity) originated two years prior to current fiscal year.

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Amount excluding accrued interest of investment in debt security measured at amortized cost (held-to-maturity) originated in fiscal year prior to current fiscal year.

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