Debt (Details) - USD ($) $ in Millions	Dec. 31, 2021	Jun. 08, 2021	Dec. 31, 2020	Apr. 27, 2020	Mar. 04, 2019
Schedule of debt
Commercial paper	$ 100		$ 100
Total short-term debt	100		100
Total long-term debt	7,254		6,504
Total debt principal	7,354		6,604
Unamortized fair value adjustment	39		41
Unamortized debt issuance costs	(103)		(95)
Total debt	7,290		6,550
Senior Notes [Member] | 7.75% Senior notes due April 15, 2026 [Member]
Schedule of debt
Total long-term debt	$ 200		$ 200
Interest rate (percent)	7.75%		7.75%
Senior Notes [Member] | 6.375% Senior notes due March 15, 2033 [Member]
Schedule of debt
Total long-term debt	$ 500		$ 500
Interest rate (percent)	6.375%		6.375%
Senior Notes [Member] | 6.75% Senior notes due June 20, 2036 [Member]
Schedule of debt
Total long-term debt	$ 400		$ 400
Interest rate (percent)	6.75%		6.75%
Senior Notes [Member] | 6.25% Senior notes due June 15, 2037 [Member]
Schedule of debt
Total long-term debt	$ 800		$ 800
Interest rate (percent)	6.25%		6.25%
Senior Notes [Member] | 5.35% Senior notes due November 1, 2040 [Member]
Schedule of debt
Total long-term debt	$ 750		$ 750
Interest rate (percent)	5.35%		5.35%
Senior Notes [Member] | 4.60% Senior notes due August 1, 2043 [Member]
Schedule of debt
Total long-term debt	$ 500		$ 500
Interest rate (percent)	4.60%		4.60%
Senior Notes [Member] | 4.30% Senior notes due August 25, 2045 [Member]
Schedule of debt
Total long-term debt	$ 400		$ 400
Interest rate (percent)	4.30%		4.30%
Senior Notes [Member] | 3.75% Senior notes due May 15, 2046 [Member]
Schedule of debt
Total long-term debt	$ 500		$ 500
Interest rate (percent)	3.75%		3.75%
Senior Notes [Member] | 4.00% Senior notes due May 30, 2047 [Member]
Schedule of debt
Total long-term debt	$ 700		$ 700
Interest rate (percent)	4.00%		4.00%
Senior Notes [Member] | 4.05% Senior notes due March 7, 2048 [Member]
Schedule of debt
Total long-term debt	$ 500		$ 500
Interest rate (percent)	4.05%		4.05%
Senior Notes [Member] | 4.10% Senior notes due March 4, 2049 [Member]
Schedule of debt
Total long-term debt	$ 500		$ 500
Interest rate (percent)	4.10%		4.10%		4.10%
Senior Notes [Member] | 2.55% Senior notes due April 27, 2050 [Member]
Schedule of debt
Total long-term debt	$ 500		$ 500
Interest rate (percent)	2.55%			2.55%
Senior Notes [Member] | 3.050% Senior notes due June 8, 2051 [Member]
Schedule of debt
Total long-term debt	$ 750
Interest rate (percent)	3.05%	3.05%
Junior Subordinated Debt [Member] | 7.625% Junior subordinated debentures due December 15, 2027 [Member]
Schedule of debt
Total long-term debt	$ 125		125
Unamortized fair value adjustment	$ 8		$ 10
Interest rate (percent)	7.625%		7.625%
Junior Subordinated Debt [Member] | 8.50% Junior subordinated debentures due December 15, 2045 [Member]
Schedule of debt
Total long-term debt	$ 56		$ 56
Unamortized fair value adjustment	$ 14		$ 14
Interest rate (percent)	8.50%		8.50%
Junior Subordinated Debt [Member] | 8.312% Junior subordinated debentures due July 1, 2046 [Member]
Schedule of debt
Total long-term debt	$ 73		$ 73
Unamortized fair value adjustment	$ 17		$ 17
Interest rate (percent)	8.312%		8.312%