Investments - Investments by Category (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Current
Investments including assets of business held for sale		$ 1,351
Investments classified as assets of business held for sale		(414)
Investments per Consolidated Balance Sheets	$ 1,331	937
Long-term
Investments including assets of business held for sale		28,837
Investments classified as assets of business held for sale		(7,295)
Investments per Consolidated Balance Sheets	23,262	21,542
Total
Investments including assets of business held for sale		30,188
Investments classified as assets of business held for sale		(7,709)
Investments per Consolidated Balance Sheets	24,593	22,479
Held-for-Sale
Total
Investments held-for-sale		7,700
Disposed of by Sale
Total
Investments held-for-sale	8,400
Debt securities
Current
Investments including assets of business held for sale		928
Investments per Consolidated Balance Sheets	959
Long-term
Investments including assets of business held for sale		22,827
Investments per Consolidated Balance Sheets	17,172
Total
Investments including assets of business held for sale		23,755
Investments per Consolidated Balance Sheets	18,131
Equity securities
Current
Investments including assets of business held for sale		0
Investments per Consolidated Balance Sheets	0
Long-term
Investments including assets of business held for sale		303
Investments per Consolidated Balance Sheets	501
Total
Investments including assets of business held for sale		303
Investments per Consolidated Balance Sheets	501
Commercial mortgage loans
Current
Investments including assets of business held for sale		0
Investments per Consolidated Balance Sheets	13
Long-term
Investments including assets of business held for sale		1,947
Investments per Consolidated Balance Sheets	1,406
Total
Investments including assets of business held for sale		1,947
Investments per Consolidated Balance Sheets	1,419
Policy loans
Current
Investments including assets of business held for sale		0
Investments per Consolidated Balance Sheets	0
Long-term
Investments including assets of business held for sale		1,357
Investments per Consolidated Balance Sheets	1,351
Total
Investments including assets of business held for sale		1,357
Investments per Consolidated Balance Sheets	1,351
Other long-term investments
Current
Investments including assets of business held for sale		0
Investments per Consolidated Balance Sheets	0
Long-term
Investments including assets of business held for sale		2,403
Investments per Consolidated Balance Sheets	2,832
Total
Investments including assets of business held for sale		2,403
Investments per Consolidated Balance Sheets	2,832
Short-term investments
Current
Investments including assets of business held for sale		423
Investments per Consolidated Balance Sheets	359
Long-term
Investments including assets of business held for sale		0
Investments per Consolidated Balance Sheets	0
Total
Investments including assets of business held for sale		$ 423
Investments per Consolidated Balance Sheets	$ 359

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