Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 1,425	$ 1,570	$ 3,947	$ 4,341
Net actuarial losses of defined benefit plans:
Adjustments	5	3	0	2
Recognized within net income	9	15	30	33
Prior service credit of defined benefit plans:
Recognized within net income	0	(1)	0	(3)
Derivative instruments:
Change in fair value - post adoption	0		0
Change in fair value - pre adoption		0		(2)
Other comprehensive income (loss)	14	17	30	30
Total comprehensive income	$ 1,439	$ 1,587	$ 3,977	$ 4,371

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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