Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total	Members Equity	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2015		$ 34,984	$ 48
Increase (Decrease) in Total Equity [Roll Forward]
Comprehensive income, net of tax	$ 3,640	3,569	71
Cash distributions to Parent	(2,500)	(2,500)	0
Balance at Dec. 31, 2016	36,172	36,053	119
Increase (Decrease) in Total Equity [Roll Forward]
Comprehensive income, net of tax	11,412	11,300	112
Cash distributions to Parent	(4,575)	(4,575)	0
Balance at Dec. 31, 2017	43,009	42,778	231
Increase (Decrease) in Total Equity [Roll Forward]
Comprehensive income, net of tax	5,093	5,219	(126)
Cash distributions to Parent	(5,450)	(5,450)	0
Balance at Dec. 31, 2018	42,649	42,519	130
Cumulative Effect of New Accounting Principle in Period of Adoption | Accounting Standards Update 2016-01 [Member]	0	1	(1)
Cumulative Effect of New Accounting Principle in Period of Adoption | Accounting Standards Update 2018-02 [Member] [Member]	0	(26)	26
Cumulative Effect of New Accounting Principle in Period of Adoption | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]	$ (3)	$ (3)	$ 0