Insurance is a contract between an individual or entity and an insurance company, whereby the individual or entity pays a premium in exchange for the promise of financial protection against specific risks or losses. An insurance company is a business that sells insurance policies and assumes the risk of paying out claims in the event of a covered loss or damage.

Here are the top 10 largest insurance companies in the United States based on total assets, according to the National Association of Insurance Commissioners (NAIC) as of year-end 2020:

1. UnitedHealth Group
2. Berkshire Hathaway
3. MetLife
4. Prudential Financial
5. New York Life
6. AIG (American International Group)
7. Anthem
8. Allstate
9. State Farm
10. Northwestern Mutual

Little Bit Details of Above Mention Company You Should Be Check and Update According to this Company List,

1. UnitedHealth Group: Based in Minnesota, UnitedHealth Group is primarily a health insurance company, but also offers other healthcare-related services such as pharmacy benefits management and healthcare data analytics. It had total assets of over $330 billion in 2020.
2. Berkshire Hathaway: Led by renowned investor Warren Buffett, Berkshire Hathaway is a conglomerate with holdings in a wide range of industries including insurance, utilities, and consumer goods. Its insurance subsidiaries include GEICO and Berkshire Hathaway Specialty Insurance. Berkshire Hathaway had total assets of over $853 billion in 2020.
3. MetLife: Based in New York, MetLife is a life insurance company that also offers other financial products such as annuities and employee benefits. It had total assets of over $744 billion in 2020.
4. Prudential Financial: Also based in New York, Prudential Financial is a diversified financial services company that offers life insurance, annuities, retirement products, and investment management. It had total assets of over $900 billion in 2020.
5. New York Life: As its name suggests, New York Life is also a life insurance company based in New York. It offers various life insurance and annuity products, as well as investment management and other financial services. It had total assets of over $328 billion in 2020.
6. AIG (American International Group): AIG is a multinational insurance company with operations in more than 80 countries. It offers property and casualty insurance, life insurance, and retirement products, among other services. It had total assets of over $537 billion in 2020.
7. Anthem: Based in Indiana, Anthem is a health insurance company that primarily operates in the Blue Cross Blue Shield network. It also offers dental, vision, and disability insurance, as well as various wellness programs. It had total assets of over $93 billion in 2020.
8. Allstate: Allstate is a personal lines insurer that offers various types of insurance, including auto, home, and life insurance. It also provides various other financial products and services, such as investment advisory and retirement planning. It had total assets of over $144 billion in 2020.
9. State Farm: Also primarily a personal lines insurer, State Farm offers auto, home, and life insurance, as well as other financial products such as mutual funds and banking services. It is known for its extensive network of agents. It had total assets of over $278 billion in 2020.
10. Northwestern Mutual: Based in Wisconsin, Northwestern Mutual is a life insurance company that also offers annuities, disability insurance, and other financial products. It is known for its focus on financial planning and advisory services. It had total assets of over $308 billion in 2020.