Restructuring - Restructuring Expense by Type (Details) - Organizational restructuring - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses	$ 37		$ 56
Cumulative Amounts Incurred to Date	316		316
Minimum
Restructuring Cost and Reserve [Line Items]
Expected costs	250		250
Maximum
Restructuring Cost and Reserve [Line Items]
Expected costs	300		300
Continuing Operations
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses	21	$ 55	36	$ 138
Cumulative Amounts Incurred to Date	286		286
Discontinued Operations [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses	16		20
Cumulative Amounts Incurred to Date	30		30
Restructuring Charges, expenses related to Individual Life Transaction	22		26
Severance benefits
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses	(5)	4	(8)	51
Cumulative Amounts Incurred to Date	50		50
Transition Costs
Restructuring Cost and Reserve [Line Items]
Total restructuring expenses	42	$ 51	64	$ 87
Cumulative Amounts Incurred to Date	$ 266		$ 266