Changes in Accumulated Other Comprehensive Income (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 21,006,000,000	$ 22,218,000,000	$ 23,071,000,000	$ 22,290,000,000
Net unrealized gains (losses)	(5,000,000)	26,000,000	52,000,000	43,000,000
Decrease due to amounts reclassified into earnings	(3,000,000)		(3,000,000)
Net translation gains (losses) on investments in foreign operations	465,000,000	(123,000,000)	(589,000,000)	47,000,000
Net gains (losses) related to hedges of investments in foreign operations	(339,000,000)	87,000,000	393,000,000	(75,000,000)
Pension and other postretirement benefits	(33,000,000)	3,000,000	(27,000,000)	(24,000,000)
Other comprehensive income (loss)	85,000,000	(7,000,000)	(174,000,000)	(9,000,000)
Ending Balance	21,062,000,000	23,092,000,000	21,062,000,000	23,092,000,000
Tax impact for the changes in each component of accumulated other comprehensive (loss) income
Net unrealized debt securities	(2,000,000)	9,000,000	16,000,000	13,000,000
Net translation on investments in foreign operations	(6,000,000)	1,000,000	24,000,000	15,000,000
Net hedges on investments in foreign operations	(106,000,000)	28,000,000	124,000,000	(22,000,000)
Pension and other postretirement benefits	(1,000,000)	4,000,000	11,000,000	(7,000,000)
Total tax impact	(115,000,000)	42,000,000	175,000,000	(1,000,000)
Reclassification out of AOCI	3,000,000	0	3,000,000	0
Net Unrealized Gains (Losses) on Debt Securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	90,000,000	9,000,000	33,000,000	(8,000,000)
Net unrealized gains (losses)	(5,000,000)	26,000,000	52,000,000	43,000,000
Decrease due to amounts reclassified into earnings	0		0
Net translation gains (losses) on investments in foreign operations	0	0	0	0
Net gains (losses) related to hedges of investments in foreign operations	0	0	0	0
Pension and other postretirement benefits	0	0	0	0
Other comprehensive income (loss)	(5,000,000)	26,000,000	52,000,000	43,000,000
Ending Balance	85,000,000	35,000,000	85,000,000	35,000,000
Foreign Currency Translation Adjustments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(2,511,000,000)	(2,125,000,000)	(2,189,000,000)	(2,133,000,000)
Net unrealized gains (losses)	0	0	0	0
Decrease due to amounts reclassified into earnings	(3,000,000)		(3,000,000)
Net translation gains (losses) on investments in foreign operations	465,000,000	(123,000,000)	(589,000,000)	47,000,000
Net gains (losses) related to hedges of investments in foreign operations	(339,000,000)	87,000,000	393,000,000	(75,000,000)
Pension and other postretirement benefits	0	0	0	0
Other comprehensive income (loss)	123,000,000	(36,000,000)	(199,000,000)	(28,000,000)
Ending Balance	(2,388,000,000)	(2,161,000,000)	(2,388,000,000)	(2,161,000,000)
Net Unrealized Pension and Other Postretirement Gains (Losses) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(575,000,000)	(483,000,000)	(581,000,000)	(456,000,000)
Net unrealized gains (losses)	0	0	0	0
Decrease due to amounts reclassified into earnings	0		0
Net translation gains (losses) on investments in foreign operations	0	0	0	0
Net gains (losses) related to hedges of investments in foreign operations	0	0	0	0
Pension and other postretirement benefits	(33,000,000)	3,000,000	(27,000,000)	(24,000,000)
Other comprehensive income (loss)	(33,000,000)	3,000,000	(27,000,000)	(24,000,000)
Ending Balance	(608,000,000)	(480,000,000)	(608,000,000)	(480,000,000)
Accumulated Other Comprehensive (Loss) Income [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(2,996,000,000)	(2,599,000,000)	(2,737,000,000)	(2,597,000,000)
Net gains (losses) related to hedges of investments in foreign operations	(339,000,000)	87,000,000	393,000,000	(75,000,000)
Ending Balance	$ (2,911,000,000)	$ (2,606,000,000)	$ (2,911,000,000)	$ (2,606,000,000)