Changes in Accumulated Other Comprehensive Income (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 21,062,000,000	$ 23,092,000,000	$ 23,071,000,000	$ 22,290,000,000
Net unrealized gains (losses)	(9,000,000)	3,000,000	43,000,000	46,000,000
Decrease due to amounts reclassified into earnings			(3,000,000)
Net translation gains (losses) on investments in foreign operations	210,000,000	(197,000,000)	(379,000,000)	(150,000,000)
Net gains (losses) related to hedges of investments in foreign operations	(170,000,000)	138,000,000	223,000,000	63,000,000
Pension and other postretirement benefits	8,000,000	1,000,000	(19,000,000)	(23,000,000)
Other comprehensive income (loss)	39,000,000	(55,000,000)	(135,000,000)	(64,000,000)
Ending Balance	21,869,000,000	23,025,000,000	21,869,000,000	23,025,000,000
Tax impact for the changes in each component of accumulated other comprehensive (loss) income
Net unrealized debt securities	(3,000,000)	1,000,000	13,000,000	14,000,000
Net translation on investments in foreign operations	(14,000,000)	(4,000,000)	10,000,000	11,000,000
Net hedges on investments in foreign operations	(57,000,000)	45,000,000	67,000,000	23,000,000
Pension and other postretirement benefits	(1,000,000)	2,000,000	10,000,000	(5,000,000)
Total tax impact	(75,000,000)	44,000,000	100,000,000	43,000,000
Reclassification out of AOCI	0	0	3,000,000	0
Net Unrealized Gains (Losses) on Debt Securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	85,000,000	35,000,000	33,000,000	(8,000,000)
Net unrealized gains (losses)	(9,000,000)	3,000,000	43,000,000	46,000,000
Decrease due to amounts reclassified into earnings			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)	(9,000,000)	3,000,000	43,000,000	46,000,000
Ending Balance	76,000,000	38,000,000	76,000,000	38,000,000
Foreign Currency Translation Adjustments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(2,388,000,000)	(2,161,000,000)	(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)
Net translation gains (losses) on investments in foreign operations	210,000,000	(197,000,000)	(379,000,000)	(150,000,000)
Net gains (losses) related to hedges of investments in foreign operations	(170,000,000)	138,000,000	223,000,000	63,000,000
Pension and other postretirement benefits	0	0	0	0
Other comprehensive income (loss)	40,000,000	(59,000,000)	(159,000,000)	(87,000,000)
Ending Balance	(2,348,000,000)	(2,220,000,000)	(2,348,000,000)	(2,220,000,000)
Net Unrealized Pension and Other Postretirement Gains (Losses) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(608,000,000)	(480,000,000)	(581,000,000)	(456,000,000)
Net unrealized gains (losses)	0	0	0	0
Decrease due to amounts reclassified into earnings			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	8,000,000	1,000,000	(19,000,000)	(23,000,000)
Other comprehensive income (loss)	8,000,000	1,000,000	(19,000,000)	(23,000,000)
Ending Balance	(600,000,000)	(479,000,000)	(600,000,000)	(479,000,000)
Accumulated Other Comprehensive (Loss) Income [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(2,911,000,000)	(2,606,000,000)	(2,737,000,000)	(2,597,000,000)
Net gains (losses) related to hedges of investments in foreign operations	(170,000,000)	138,000,000	223,000,000	(63,000,000)
Ending Balance	$ (2,872,000,000)	$ (2,661,000,000)	$ (2,872,000,000)	$ (2,661,000,000)